Functions (GNU libiberty)

## 3 Function, Variable, and Macro Listing. ¶

Replacement: `void*` alloca `(size_t size)` ¶

  This function allocates memory which will be automatically reclaimed after the procedure exits. The `libiberty` implementation does not free the memory immediately but will do so eventually during subsequent calls to this function. Memory is allocated using `xmalloc` under normal circumstances.

  The header file `alloca-conf.h` can be used in conjunction with the GNU Autoconf test `AC_FUNC_ALLOCA` to test for and properly make available this function. The `AC_FUNC_ALLOCA` test requires that client code use a block of preprocessor code to be safe (see the Autoconf manual for more); this header incorporates that logic and more, including the possibility of a GCC built-in function.

Extension: `int` asprintf `(char **resptr, const char *format, ...)` ¶

  Like `sprintf`, but instead of passing a pointer to a buffer, you pass a pointer to a pointer. This function will compute the size of the buffer needed, allocate memory with `malloc`, and store a pointer to the allocated memory in `*resptr`. The value returned is the same as `sprintf` would return. If memory could not be allocated, minus one is returned and `NULL` is stored in `*resptr`.

Supplemental: `int` atexit `(void (*f)())` ¶

  Causes function f to be called at exit. Returns 0.

Supplemental: `char*` basename `(const char *name)` ¶

  Returns a pointer to the last component of pathname name. Behavior is undefined if the pathname ends in a directory separator.

Supplemental: `int` bcmp `(char *x, char *y, int count)` ¶

  Compares the first count bytes of two areas of memory. Returns zero if they are the same, nonzero otherwise. Returns zero if count is zero. A nonzero result only indicates a difference, it does not indicate any sorting order (say, by having a positive result mean x sorts before y).

Supplemental: `void` bcopy `(char *in, char *out, int length)` ¶

  Copies length bytes from memory region in to region out. The use of `bcopy` is deprecated in new programs.

Supplemental: `void*` bsearch `(const void *key, const void *base, size_t nmemb, size_t size, int (*compar)(const void *, const void *))` ¶

  Performs a search over an array of nmemb elements pointed to by base for a member that matches the object pointed to by key. The size of each member is specified by size. The array contents should be sorted in ascending order according to the compar comparison function. This routine should take two arguments pointing to the key and to an array member, in that order, and should return an integer less than, equal to, or greater than zero if the key object is respectively less than, matching, or greater than the array member.

Supplemental: `void*` bsearch_r `(const void *key, const void *base, size_t nmemb, size_t size, int (*compar)(const void *, const void *, void *), void *arg)` ¶

  Performs a search over an array of nmemb elements pointed to by base for a member that matches the object pointed to by key. The size of each member is specified by size. The array contents should be sorted in ascending order according to the compar comparison function. This routine should take three arguments: the first two point to the key and to an array member, and the last is passed down unchanged from `bsearch_r`’s last argument. It should return an integer less than, equal to, or greater than zero if the key object is respectively less than, matching, or greater than the array member.

Extension: `char**` buildargv `(char *sp)` ¶

  Given a pointer to a string, parse the string extracting fields separated by whitespace and optionally enclosed within either single or double quotes (which are stripped off), and build a vector of pointers to copies of the string for each field. The input string remains unchanged. The last element of the vector is followed by a `NULL` element.

  All of the memory for the pointer array and copies of the string is obtained from `xmalloc`. All of the memory can be returned to the system with the single function call `freeargv`, which takes the returned result of `buildargv`, as it’s argument.

  Returns a pointer to the argument vector if successful. Returns `NULL` if sp is `NULL` or if there is insufficient memory to complete building the argument vector.

  If the input is a null string (as opposed to a `NULL` pointer), then buildarg returns an argument vector that has one arg, a null string.

Supplemental: `void` bzero `(char *mem, int count)` ¶

  Zeros count bytes starting at mem. Use of this function is deprecated in favor of `memset`.

Supplemental: `void*` calloc `(size_t nelem, size_t elsize)` ¶

  Uses `malloc` to allocate storage for nelem objects of elsize bytes each, then zeros the memory.

Extension: `int` canonical_filename_eq `(const char *a, const char *b)` ¶

  Return non-zero if file names a and b are equivalent. This function compares the canonical versions of the filenames as returned by `lrealpath()`, so that so that different file names pointing to the same underlying file are treated as being identical.

Extension: `char*` choose_temp_base `(void)` ¶

  Return a prefix for temporary file names or `NULL` if unable to find one. The current directory is chosen if all else fails so the program is exited if a temporary directory can’t be found (`mktemp` fails). The buffer for the result is obtained with `xmalloc`.

  This function is provided for backwards compatibility only. Its use is not recommended.

Replacement: `const` char* `choose_tmpdir ()` ¶

  Returns a pointer to a directory path suitable for creating temporary files in.

Supplemental: `long` clock `(void)` ¶

  Returns an approximation of the CPU time used by the process as a `clock_t`; divide this number by ‘`CLOCKS_PER_SEC`’ to get the number of seconds used.

Extension: `char*` concat `(const char *s1, const char *s2, …, `NULL`)` ¶

  Concatenate zero or more of strings and return the result in freshly `xmalloc`ed memory. The argument list is terminated by the first `NULL` pointer encountered. Pointers to empty strings are ignored.

Extension: `int` countargv `(char * const *argv)` ¶

  Return the number of elements in argv. Returns zero if argv is NULL.

Extension: `unsigned int` crc32 `(const unsigned char *buf, int len, unsigned int init)` ¶

  Compute the 32-bit CRC of buf which has length len. The starting value is init; this may be used to compute the CRC of data split across multiple buffers by passing the return value of each call as the init parameter of the next.

  This is used by the `gdb` remote protocol for the ‘`qCRC`’ command. In order to get the same results as gdb for a block of data, you must pass the first CRC parameter as `0xffffffff`.

  This CRC can be specified as:

  Width : 32 Poly : 0x04c11db7 Init : parameter, typically 0xffffffff RefIn : false RefOut : false XorOut : 0

  This differs from the "standard" CRC-32 algorithm in that the values are not reflected, and there is no final XOR value. These differences make it easy to compose the values of multiple blocks.

Extension: `char**` dupargv `(char * const *vector)` ¶

  Duplicate an argument vector. Simply scans through vector, duplicating each argument until the terminating `NULL` is found. Returns a pointer to the argument vector if successful. Returns `NULL` if there is insufficient memory to complete building the argument vector.

Extension: `int` errno_max `(void)` ¶

  Returns the maximum `errno` value for which a corresponding symbolic name or message is available. Note that in the case where we use the `sys_errlist` supplied by the system, it is possible for there to be more symbolic names than messages, or vice versa. In fact, the manual page for `perror(3C)` explicitly warns that one should check the size of the table (`sys_nerr`) before indexing it, since new error codes may be added to the system before they are added to the table. Thus `sys_nerr` might be smaller than value implied by the largest `errno` value defined in `<errno.h>`.

  We return the maximum value that can be used to obtain a meaningful symbolic name or message.

Extension: `void` expandargv `(int *argcp, char ***argvp)` ¶

  The argcp and `argvp` arguments are pointers to the usual `argc` and `argv` arguments to `main`. This function looks for arguments that begin with the character ‘`@`’. Any such arguments are interpreted as “response files”. The contents of the response file are interpreted as additional command line options. In particular, the file is separated into whitespace-separated strings; each such string is taken as a command-line option. The new options are inserted in place of the option naming the response file, and `*argcp` and `*argvp` will be updated. If the value of `*argvp` is modified by this function, then the new value has been dynamically allocated and can be deallocated by the caller with `freeargv`. However, most callers will simply call `expandargv` near the beginning of `main` and allow the operating system to free the memory when the program exits.

Extension: `int` fdmatch `(int fd1, int fd2)` ¶

  Check to see if two open file descriptors refer to the same file. This is useful, for example, when we have an open file descriptor for an unnamed file, and the name of a file that we believe to correspond to that fd. This can happen when we are exec’d with an already open file (`stdout` for example) or from the SVR4 `/proc` calls that return open file descriptors for mapped address spaces. All we have to do is open the file by name and check the two file descriptors for a match, which is done by comparing major and minor device numbers and inode numbers.

Extension: `FILE *` fdopen_unlocked `(int fildes, const char * mode)` ¶

  Opens and returns a `FILE` pointer via `fdopen`. If the operating system supports it, ensure that the stream is setup to avoid any multi-threaded locking. Otherwise return the `FILE` pointer unchanged.

Supplemental: `int` ffs `(int valu)` ¶

  Find the first (least significant) bit set in valu. Bits are numbered from right to left, starting with bit 1 (corresponding to the value 1). If valu is zero, zero is returned.

Extension: `int` filename_cmp `(const char *s1, const char *s2)` ¶

  Return zero if the two file names s1 and s2 are equivalent. If not equivalent, the returned value is similar to what `strcmp` would return. In other words, it returns a negative value if s1 is less than s2, or a positive value if s2 is greater than s2.

  This function does not normalize file names. As a result, this function will treat filenames that are spelled differently as different even in the case when the two filenames point to the same underlying file. However, it does handle the fact that on DOS-like file systems, forward and backward slashes are equal.

Extension: `int` filename_eq `(const void *s1, const void *s2)` ¶

  Return non-zero if file names s1 and s2 are equivalent. This function is for use with hashtab.c hash tables.

Extension: `hashval_t` filename_hash `(const void *s)` ¶

  Return the hash value for file name s that will be compared using filename_cmp. This function is for use with hashtab.c hash tables.

Extension: `int` filename_ncmp `(const char *s1, const char *s2, size_t n)` ¶

  Return zero if the two file names s1 and s2 are equivalent in range n. If not equivalent, the returned value is similar to what `strncmp` would return. In other words, it returns a negative value if s1 is less than s2, or a positive value if s2 is greater than s2.

  This function does not normalize file names. As a result, this function will treat filenames that are spelled differently as different even in the case when the two filenames point to the same underlying file. However, it does handle the fact that on DOS-like file systems, forward and backward slashes are equal.

Replacement: `int` fnmatch `(const char *pattern, const char *string, int flags)` ¶

  Matches string against pattern, returning zero if it matches, `FNM_NOMATCH` if not. pattern may contain the wildcards `?` to match any one character, `*` to match any zero or more characters, or a set of alternate characters in square brackets, like ‘`[a-gt8]`’, which match one character (`a` through `g`, or `t`, or `8`, in this example) if that one character is in the set. A set may be inverted (i.e., match anything except what’s in the set) by giving `^` or `!` as the first character in the set. To include those characters in the set, list them as anything other than the first character of the set. To include a dash in the set, list it last in the set. A backslash character makes the following character not special, so for example you could match against a literal asterisk with ‘`\*`’. To match a literal backslash, use ‘`\\`’.

  `flags` controls various aspects of the matching process, and is a boolean OR of zero or more of the following values (defined in `<fnmatch.h>`):

  `FNM_PATHNAME`
  `FNM_FILE_NAME`

    string is assumed to be a path name. No wildcard will ever match `/`.

  `FNM_NOESCAPE`

    Do not interpret backslashes as quoting the following special character.

  `FNM_PERIOD`

    A leading period (at the beginning of string, or if `FNM_PATHNAME` after a slash) is not matched by `*` or `?` but must be matched explicitly.

  `FNM_LEADING_DIR`

    Means that string also matches pattern if some initial part of string matches, and is followed by `/` and zero or more characters. For example, ‘`foo*`’ would match either ‘`foobar`’ or ‘`foobar/grill`’.

  `FNM_CASEFOLD`

    Ignores case when performing the comparison.

Extension: `FILE *` fopen_unlocked `(const char *path, const char * mode)` ¶

  Opens and returns a `FILE` pointer via `fopen`. If the operating system supports it, ensure that the stream is setup to avoid any multi-threaded locking. Otherwise return the `FILE` pointer unchanged.

Extension: `void` freeargv `(char **vector)` ¶

  Free an argument vector that was built using `buildargv`. Simply scans through vector, freeing the memory for each argument until the terminating `NULL` is found, and then frees vector itself.

Extension: `FILE *` freopen_unlocked `(const char * path, const char * mode, FILE * stream)` ¶

  Opens and returns a `FILE` pointer via `freopen`. If the operating system supports it, ensure that the stream is setup to avoid any multi-threaded locking. Otherwise return the `FILE` pointer unchanged.

Replacement: `long` get_run_time `(void)` ¶

  Returns the time used so far, in microseconds. If possible, this is the time used by this process, else it is the elapsed time since the process started.

Supplemental: `char*` getcwd `(char *pathname, int len)` ¶

  Copy the absolute pathname for the current working directory into pathname, which is assumed to point to a buffer of at least len bytes, and return a pointer to the buffer. If the current directory’s path doesn’t fit in len characters, the result is `NULL` and `errno` is set. If pathname is a null pointer, `getcwd` will obtain len bytes of space using `malloc`.

Supplemental: `int` getpagesize `(void)` ¶

  Returns the number of bytes in a page of memory. This is the granularity of many of the system memory management routines. No guarantee is made as to whether or not it is the same as the basic memory management hardware page size.

Supplemental: `char*` getpwd `(void)` ¶

  Returns the current working directory. This implementation caches the result on the assumption that the process will not call `chdir` between calls to `getpwd`.

Supplemental: `int` gettimeofday `(struct timeval *tp, void *tz)` ¶

  Writes the current time to tp. This implementation requires that tz be NULL. Returns 0 on success, -1 on failure.

Extension: `void` hex_init `(void)` ¶

  Initializes the array mapping the current character set to corresponding hex values. This function must be called before any call to `hex_p` or `hex_value`. If you fail to call it, a default ASCII-based table will normally be used on ASCII systems.

Extension: `int` hex_p `(int c)` ¶

  Evaluates to non-zero if the given character is a valid hex character, or zero if it is not. Note that the value you pass will be cast to `unsigned char` within the macro.

Extension: `unsigned int` hex_value `(int c)` ¶

  Returns the numeric equivalent of the given character when interpreted as a hexadecimal digit. The result is undefined if you pass an invalid hex digit. Note that the value you pass will be cast to `unsigned char` within the macro.

  The `hex_value` macro returns `unsigned int`, rather than signed `int`, to make it easier to use in parsing addresses from hex dump files: a signed `int` would be sign-extended when converted to a wider unsigned type — like `bfd_vma`, on some systems.

Extension: HOST_CHARSET ¶

  This macro indicates the basic character set and encoding used by the host: more precisely, the encoding used for character constants in preprocessor ‘`#if`’ statements (the C "execution character set"). It is defined by `safe-ctype.h`, and will be an integer constant with one of the following values:

  `HOST_CHARSET_UNKNOWN` ¶

    The host character set is unknown - that is, not one of the next two possibilities.

  `HOST_CHARSET_ASCII` ¶

    The host character set is ASCII.

  `HOST_CHARSET_EBCDIC` ¶

    The host character set is some variant of EBCDIC. (Only one of the nineteen EBCDIC varying characters is tested; exercise caution.)

Supplemental: `htab_t` htab_create_typed_alloc `(size_t size, htab_hash hash_f, htab_eq eq_f, htab_del del_f, htab_alloc alloc_tab_f, htab_alloc alloc_f, htab_free free_f)` ¶

  This function creates a hash table that uses two different allocators alloc_tab_f and alloc_f to use for allocating the table itself and its entries respectively. This is useful when variables of different types need to be allocated with different allocators.

  The created hash table is slightly larger than size and it is initially empty (all the hash table entries are `HTAB_EMPTY_ENTRY`). The function returns the created hash table, or `NULL` if memory allocation fails.

Supplemental: `char*` index `(char *s, int c)` ¶

  Returns a pointer to the first occurrence of the character c in the string s, or `NULL` if not found. The use of `index` is deprecated in new programs in favor of `strchr`.

Supplemental: `void` insque `(struct qelem *elem, struct qelem *pred)` ¶
Supplemental: `void` remque `(struct qelem *elem)` ¶

  Routines to manipulate queues built from doubly linked lists. The `insque` routine inserts elem in the queue immediately after pred. The `remque` routine removes elem from its containing queue. These routines expect to be passed pointers to structures which have as their first members a forward pointer and a back pointer, like this prototype (although no prototype is provided):

      struct qelem {
        struct qelem *q_forw;
        struct qelem *q_back;
        char q_data[];
      };

Extension: ISALPHA (c) ¶
Extension: ISALNUM (c) ¶
Extension: ISBLANK (c) ¶
Extension: ISCNTRL (c) ¶
Extension: ISDIGIT (c) ¶
Extension: ISGRAPH (c) ¶
Extension: ISLOWER (c) ¶
Extension: ISPRINT (c) ¶
Extension: ISPUNCT (c) ¶
Extension: ISSPACE (c) ¶
Extension: ISUPPER (c) ¶
Extension: ISXDIGIT (c) ¶

  These twelve macros are defined by `safe-ctype.h`. Each has the same meaning as the corresponding macro (with name in lowercase) defined by the standard header `ctype.h`. For example, `ISALPHA` returns true for alphabetic characters and false for others. However, there are two differences between these macros and those provided by `ctype.h`:

  - These macros are guaranteed to have well-defined behavior for all values representable by `signed char` and `unsigned char`, and for `EOF`.
  - These macros ignore the current locale; they are true for these fixed sets of characters:

    `ALPHA` | `A-Za-z`
    `ALNUM` | `A-Za-z0-9`
    `BLANK` | `space tab`
    `CNTRL` | `!PRINT`
    `DIGIT` | `0-9`
    `GRAPH` | `ALNUM || PUNCT`
    `LOWER` | `a-z`
    `PRINT` | `GRAPH ||` `space`
    `PUNCT` | ``~!@#$%^&*()_-=+[{]}\|;:'",<.>/?`
    `SPACE` | `space tab \n \r \f \v`
    `UPPER` | `A-Z`
    `XDIGIT` | `0-9A-Fa-f`

    Note that, if the host character set is ASCII or a superset thereof, all these macros will return false for all values of `char` outside the range of 7-bit ASCII. In particular, both ISPRINT and ISCNTRL return false for characters with numeric values from 128 to 255.

Extension: ISIDNUM (c) ¶
Extension: ISIDST (c) ¶
Extension: IS_VSPACE (c) ¶
Extension: IS_NVSPACE (c) ¶
Extension: IS_SPACE_OR_NUL (c) ¶
Extension: IS_ISOBASIC (c) ¶

  These six macros are defined by `safe-ctype.h` and provide additional character classes which are useful when doing lexical analysis of C or similar languages. They are true for the following sets of characters:

  `IDNUM` | `A-Za-z0-9_`
  `IDST` | `A-Za-z_`
  `VSPACE` | `\r \n`
  `NVSPACE` | `space tab \f \v \0`
  `SPACE_OR_NUL` | `VSPACE || NVSPACE`
  `ISOBASIC` | `VSPACE || NVSPACE || PRINT`

Replacement: `const char*` lbasename `(const char *name)` ¶

  Given a pointer to a string containing a typical pathname (‘`/usr/src/cmd/ls/ls.c`’ for example), returns a pointer to the last component of the pathname (‘`ls.c`’ in this case). The returned pointer is guaranteed to lie within the original string. This latter fact is not true of many vendor C libraries, which return special strings or modify the passed strings for particular input.

  In particular, the empty string returns the same empty string, and a path ending in `/` returns the empty string after it.

Replacement: `const char*` lrealpath `(const char *name)` ¶

  Given a pointer to a string containing a pathname, returns a canonical version of the filename. Symlinks will be resolved, and “.” and “..” components will be simplified. The returned value will be allocated using `malloc`, or `NULL` will be returned on a memory allocation error.

Extension: `const char*` make_relative_prefix `(const char *progname, const char *bin_prefix, const char *prefix)` ¶

  Given three paths progname, bin_prefix, prefix, return the path that is in the same position relative to progname’s directory as prefix is relative to bin_prefix. That is, a string starting with the directory portion of progname, followed by a relative pathname of the difference between bin_prefix and prefix.

  If progname does not contain any directory separators, `make_relative_prefix` will search `PATH` to find a program named progname. Also, if progname is a symbolic link, the symbolic link will be resolved.

  For example, if bin_prefix is `/alpha/beta/gamma/gcc/delta`, prefix is `/alpha/beta/gamma/omega/`, and progname is `/red/green/blue/gcc`, then this function will return `/red/green/blue/../../omega/`.

  The return value is normally allocated via `malloc`. If no relative prefix can be found, return `NULL`.

Replacement: `char*` make_temp_file `(const char *suffix)` ¶

  Return a temporary file name (as a string) or `NULL` if unable to create one. suffix is a suffix to append to the file name. The string is `malloc`ed, and the temporary file has been created.

Supplemental: `void*` memchr `(const void *s, int c, size_t n)` ¶

  This function searches memory starting at `*s` for the character c. The search only ends with the first occurrence of c, or after length characters; in particular, a null character does not terminate the search. If the character c is found within length characters of `*s`, a pointer to the character is returned. If c is not found, then `NULL` is returned.

Supplemental: `void*` memrchr `(const void *s, int c, size_t n)` ¶

  This function searches memory for the character c in reverse order, starting at `*s+n-1` . The search only ends with the first occurrence of c, or when the start us reached; in particular, a null character does not terminate the search. If the character c is found within length characters of `*s`, a pointer to the character is returned. If c is not found, then `NULL` is returned.

Supplemental: `int` memcmp `(const void *x, const void *y, size_t count)` ¶

  Compares the first count bytes of two areas of memory. Returns zero if they are the same, a value less than zero if x is lexically less than y, or a value greater than zero if x is lexically greater than y. Note that lexical order is determined as if comparing unsigned char arrays.

Supplemental: `void*` memcpy `(void *out, const void *in, size_t length)` ¶

  Copies length bytes from memory region in to region out. Returns a pointer to out.

Supplemental: `void*` memmem `(const void *haystack, size_t haystack_len const void *needle, size_t needle_len)` ¶

  Returns a pointer to the first occurrence of needle (length needle_len) in haystack (length haystack_len). Returns `NULL` if not found.

Supplemental: `void*` memmove `(void *from, const void *to, size_t count)` ¶

  Copies count bytes from memory area from to memory area to, returning a pointer to to.

Supplemental: `void*` mempcpy `(void *out, const void *in, size_t length)` ¶

  Copies length bytes from memory region in to region out. Returns a pointer to out + length.

Supplemental: `void*` memset `(void *s, int c, size_t count)` ¶

  Sets the first count bytes of s to the constant byte c, returning a pointer to s.

Replacement: `int` mkstemps `(char *pattern, int suffix_len)` ¶

  Generate a unique temporary file name from pattern. pattern has the form:

         path/ccXXXXXXsuffix

  suffix_len tells us how long suffix is (it can be zero length). The last six characters of pattern before suffix must be ‘`XXXXXX`’; they are replaced with a string that makes the filename unique. Returns a file descriptor open on the file for reading and writing.

Extension: `void` pex_free `(struct pex_obj obj)` ¶

  Clean up and free all data associated with obj. If you have not yet called `pex_get_times` or `pex_get_status`, this will try to kill the subprocesses.

Extension: `int` pex_get_status `(struct pex_obj *obj, int count, int *vector)` ¶

  Returns the exit status of all programs run using obj. count is the number of results expected. The results will be placed into vector. The results are in the order of the calls to `pex_run`. Returns 0 on error, 1 on success.

Extension: `int` pex_get_times `(struct pex_obj *obj, int count, struct pex_time *vector)` ¶

  Returns the process execution times of all programs run using obj. count is the number of results expected. The results will be placed into vector. The results are in the order of the calls to `pex_run`. Returns 0 on error, 1 on success.

  `struct pex_time` has the following fields of the type `unsigned long`: `user_seconds`, `user_microseconds`, `system_seconds`, `system_microseconds`. On systems which do not support reporting process times, all the fields will be set to `0`.

Extension: `struct pex_obj *` pex_init `(int flags, const char *pname, const char *tempbase)` ¶

  Prepare to execute one or more programs, with standard output of each program fed to standard input of the next. This is a system independent interface to execute a pipeline.

  flags is a bitwise combination of the following:

  `PEX_RECORD_TIMES` ¶

    Record subprocess times if possible.

  `PEX_USE_PIPES` ¶

    Use pipes for communication between processes, if possible.

  `PEX_SAVE_TEMPS` ¶

    Don’t delete temporary files used for communication between processes.

  pname is the name of program to be executed, used in error messages. tempbase is a base name to use for any required temporary files; it may be `NULL` to use a randomly chosen name.

Extension: `FILE *` pex_input_file `(struct pex_obj *obj, int flags, const char *in_name)` ¶

  Return a stream for a temporary file to pass to the first program in the pipeline as input.

  The name of the input file is chosen according to the same rules `pex_run` uses to choose output file names, based on in_name, obj and the `PEX_SUFFIX` bit in flags.

  Don’t call `fclose` on the returned stream; the first call to `pex_run` closes it automatically.

  If flags includes `PEX_BINARY_OUTPUT`, open the stream in binary mode; otherwise, open it in the default mode. Including `PEX_BINARY_OUTPUT` in flags has no effect on Unix.

Extension: `FILE *` pex_input_pipe `(struct pex_obj *obj, int binary)` ¶

  Return a stream fp for a pipe connected to the standard input of the first program in the pipeline; fp is opened for writing. You must have passed `PEX_USE_PIPES` to the `pex_init` call that returned obj.

  You must close fp using `fclose` yourself when you have finished writing data to the pipeline.

  The file descriptor underlying fp is marked not to be inherited by child processes.

  On systems that do not support pipes, this function returns `NULL`, and sets `errno` to `EINVAL`. If you would like to write code that is portable to all systems the `pex` functions support, consider using `pex_input_file` instead.

  There are two opportunities for deadlock using `pex_input_pipe`:

  - Most systems’ pipes can buffer only a fixed amount of data; a process that writes to a full pipe blocks. Thus, if you write to `fp` before starting the first process, you run the risk of blocking when there is no child process yet to read the data and allow you to continue. `pex_input_pipe` makes no promises about the size of the pipe’s buffer, so if you need to write any data at all before starting the first process in the pipeline, consider using `pex_input_file` instead.
  - Using `pex_input_pipe` and `pex_read_output` together may also cause deadlock. If the output pipe fills up, so that each program in the pipeline is waiting for the next to read more data, and you fill the input pipe by writing more data to fp, then there is no way to make progress: the only process that could read data from the output pipe is you, but you are blocked on the input pipe.

Extension: `const char *` pex_one `(int flags, const char *executable, char * const *argv, const char *pname, const char *outname, const char *errname, int *status, int *err)` ¶

  An interface to permit the easy execution of a single program. The return value and most of the parameters are as for a call to `pex_run`. flags is restricted to a combination of `PEX_SEARCH`, `PEX_STDERR_TO_STDOUT`, and `PEX_BINARY_OUTPUT`. outname is interpreted as if `PEX_LAST` were set. On a successful return, `*status` will be set to the exit status of the program.

Extension: `FILE *` pex_read_err `(struct pex_obj *obj, int binary)` ¶

  Returns a `FILE` pointer which may be used to read the standard error of the last program in the pipeline. When this is used, `PEX_LAST` should not be used in a call to `pex_run`. After this is called, `pex_run` may no longer be called with the same obj. binary should be non-zero if the file should be opened in binary mode. Don’t call `fclose` on the returned file; it will be closed by `pex_free`.

Extension: `FILE *` pex_read_output `(struct pex_obj *obj, int binary)` ¶

  Returns a `FILE` pointer which may be used to read the standard output of the last program in the pipeline. When this is used, `PEX_LAST` should not be used in a call to `pex_run`. After this is called, `pex_run` may no longer be called with the same obj. binary should be non-zero if the file should be opened in binary mode. Don’t call `fclose` on the returned file; it will be closed by `pex_free`.

Extension: `const char *` pex_run `(struct pex_obj *obj, int flags, const char *executable, char * const *argv, const char *outname, const char *errname, int *err)` ¶

  Execute one program in a pipeline. On success this returns `NULL`. On failure it returns an error message, a statically allocated string.

  obj is returned by a previous call to `pex_init`.

  flags is a bitwise combination of the following:

  `PEX_LAST` ¶

    This must be set on the last program in the pipeline. In particular, it should be set when executing a single program. The standard output of the program will be sent to outname, or, if outname is `NULL`, to the standard output of the calling program. Do not set this bit if you want to call `pex_read_output` (described below). After a call to `pex_run` with this bit set, pex_run may no longer be called with the same obj.

  `PEX_SEARCH` ¶

    Search for the program using the user’s executable search path.

  `PEX_SUFFIX` ¶

    outname is a suffix. See the description of outname, below.

  `PEX_STDERR_TO_STDOUT` ¶

    Send the program’s standard error to standard output, if possible.

  `PEX_BINARY_INPUT` ¶
  `PEX_BINARY_OUTPUT`
  `PEX_BINARY_ERROR`

    The standard input (output or error) of the program should be read (written) in binary mode rather than text mode. These flags are ignored on systems which do not distinguish binary mode and text mode, such as Unix. For proper behavior these flags should match appropriately—a call to `pex_run` using `PEX_BINARY_OUTPUT` should be followed by a call using `PEX_BINARY_INPUT`.

  `PEX_STDERR_TO_PIPE` ¶

    Send the program’s standard error to a pipe, if possible. This flag cannot be specified together with `PEX_STDERR_TO_STDOUT`. This flag can be specified only on the last program in pipeline.

  executable is the program to execute. argv is the set of arguments to pass to the program; normally `argv[0]` will be a copy of executable.

  outname is used to set the name of the file to use for standard output. There are two cases in which no output file will be used:

  1. if `PEX_LAST` is not set in flags, and `PEX_USE_PIPES` was set in the call to `pex_init`, and the system supports pipes
  2. if `PEX_LAST` is set in flags, and outname is `NULL`

  Otherwise the code will use a file to hold standard output. If `PEX_LAST` is not set, this file is considered to be a temporary file, and it will be removed when no longer needed, unless `PEX_SAVE_TEMPS` was set in the call to `pex_init`.

  There are two cases to consider when setting the name of the file to hold standard output.

  1. `PEX_SUFFIX` is set in flags. In this case outname may not be `NULL`. If the tempbase parameter to `pex_init` was not `NULL`, then the output file name is the concatenation of tempbase and outname. If tempbase was `NULL`, then the output file name is a random file name ending in outname.
  2. `PEX_SUFFIX` was not set in flags. In this case, if outname is not `NULL`, it is used as the output file name. If outname is `NULL`, and tempbase was not NULL, the output file name is randomly chosen using tempbase. Otherwise the output file name is chosen completely at random.

  errname is the file name to use for standard error output. If it is `NULL`, standard error is the same as the caller’s. Otherwise, standard error is written to the named file.

  On an error return, the code sets `*err` to an `errno` value, or to 0 if there is no relevant `errno`.

Extension: `const char *` pex_run_in_environment `(struct pex_obj *obj, int flags, const char *executable, char * const *argv, char * const *env, int env_size, const char *outname, const char *errname, int *err)` ¶

  Execute one program in a pipeline, permitting the environment for the program to be specified. Behaviour and parameters not listed below are as for `pex_run`.

  env is the environment for the child process, specified as an array of character pointers. Each element of the array should point to a string of the form `VAR=VALUE`, with the exception of the last element that must be `NULL`.

Extension: `int` pexecute `(const char *program, char * const *argv, const char *this_pname, const char *temp_base, char **errmsg_fmt, char **errmsg_arg, int flags)` ¶

  This is the old interface to execute one or more programs. It is still supported for compatibility purposes, but is no longer documented.

Supplemental: `void` psignal `(int signo, char *message)` ¶

  Print message to the standard error, followed by a colon, followed by the description of the signal specified by signo, followed by a newline.

Supplemental: `int` putenv `(const char *string)` ¶

  Uses `setenv` or `unsetenv` to put string into the environment or remove it. If string is of the form ‘`name=value`’ the string is added; if no ‘`=`’ is present the name is unset/removed.

Extension: `int` pwait `(int pid, int *status, int flags)` ¶

  Another part of the old execution interface.

Supplement: `long int` random `(void)` ¶
Supplement: `void` srandom `(unsigned int seed)` ¶
Supplement: `void*` initstate `(unsigned int seed, void *arg_state, unsigned long n)` ¶
Supplement: `void*` setstate `(void *arg_state)` ¶

  Random number functions. `random` returns a random number in the range 0 to `LONG_MAX`. `srandom` initializes the random number generator to some starting point determined by seed (else, the values returned by `random` are always the same for each run of the program). `initstate` and `setstate` allow fine-grained control over the state of the random number generator.

Extension: `char*` reconcat `(char *optr, const char *s1, …, `NULL`)` ¶

  Same as `concat`, except that if optr is not `NULL` it is freed after the string is created. This is intended to be useful when you’re extending an existing string or building up a string in a loop:

        str = reconcat (str, "pre-", str, NULL);

Supplemental: `int` rename `(const char *old, const char *new)` ¶

  Renames a file from old to new. If new already exists, it is removed.

Supplemental: `char*` rindex `(const char *s, int c)` ¶

  Returns a pointer to the last occurrence of the character c in the string s, or `NULL` if not found. The use of `rindex` is deprecated in new programs in favor of `strrchr`.

Supplemental: `int` setenv `(const char *name, const char *value, int overwrite)` ¶
Supplemental: `void` unsetenv `(const char *name)` ¶

  `setenv` adds name to the environment with value value. If the name was already present in the environment, the new value will be stored only if overwrite is nonzero. The companion `unsetenv` function removes name from the environment. This implementation is not safe for multithreaded code.

Supplemental: `void` setproctitle `(const char *fmt, ...)` ¶

  Set the title of a process to fmt. va args not supported for now, but defined for compatibility with BSD.

Extension: `int` signo_max `(void)` ¶

  Returns the maximum signal value for which a corresponding symbolic name or message is available. Note that in the case where we use the `sys_siglist` supplied by the system, it is possible for there to be more symbolic names than messages, or vice versa. In fact, the manual page for `psignal(3b)` explicitly warns that one should check the size of the table (`NSIG`) before indexing it, since new signal codes may be added to the system before they are added to the table. Thus `NSIG` might be smaller than value implied by the largest signo value defined in `<signal.h>`.

  We return the maximum value that can be used to obtain a meaningful symbolic name or message.

Supplemental: `int` sigsetmask `(int set)` ¶

  Sets the signal mask to the one provided in set and returns the old mask (which, for libiberty’s implementation, will always be the value `1`).

Extension: `const char *` simple_object_attributes_compare `(simple_object_attributes *attrs1, simple_object_attributes *attrs2, int *err)` ¶

  Compare attrs1 and attrs2. If they could be linked together without error, return `NULL`. Otherwise, return an error message and set `*err` to an errno value or `0` if there is no relevant errno.

Extension: `simple_object_attributes *` simple_object_fetch_attributes `(simple_object_read *simple_object, const char **errmsg, int *err)` ¶

  Fetch the attributes of simple_object. The attributes are internal information such as the format of the object file, or the architecture it was compiled for. This information will persist until `simple_object_attributes_release` is called, even if simple_object itself is released.

  On error this returns `NULL`, sets `*errmsg` to an error message, and sets `*err` to an errno value or `0` if there is no relevant errno.

Extension: `int` simple_object_find_section `(simple_object_read *simple_object off_t *offset, off_t *length, const char **errmsg, int *err)` ¶

  Look for the section name in simple_object. This returns information for the first section with that name.

  If found, return 1 and set `*offset` to the offset in the file of the section contents and set `*length` to the length of the section contents. The value in `*offset` will be relative to the offset passed to `simple_object_open_read`.

  If the section is not found, and no error occurs, `simple_object_find_section` returns `0` and set `*errmsg` to `NULL`.

  If an error occurs, `simple_object_find_section` returns `0`, sets `*errmsg` to an error message, and sets `*err` to an errno value or `0` if there is no relevant errno.

Extension: `const char *` simple_object_find_sections `(simple_object_read *simple_object, int (*pfn) (void *data, const char *name, off_t offset, off_t length), void *data, int *err)` ¶

  This function calls pfn for each section in simple_object. It calls pfn with the section name, the offset within the file of the section contents, and the length of the section contents. The offset within the file is relative to the offset passed to `simple_object_open_read`. The data argument to this function is passed along to pfn.

  If pfn returns `0`, the loop over the sections stops and `simple_object_find_sections` returns. If pfn returns some other value, the loop continues.

  On success `simple_object_find_sections` returns. On error it returns an error string, and sets `*err` to an errno value or `0` if there is no relevant errno.

Extension: `simple_object_read *` simple_object_open_read `(int descriptor, off_t offset, const char *segment_name, const char **errmsg, int *err)` ¶

  Opens an object file for reading. Creates and returns an `simple_object_read` pointer which may be passed to other functions to extract data from the object file.

  descriptor holds a file descriptor which permits reading.

  offset is the offset into the file; this will be `0` in the normal case, but may be a different value when reading an object file in an archive file.

  segment_name is only used with the Mach-O file format used on Darwin aka Mac OS X. It is required on that platform, and means to only look at sections within the segment with that name. The parameter is ignored on other systems.

  If an error occurs, this functions returns `NULL` and sets `*errmsg` to an error string and sets `*err` to an errno value or `0` if there is no relevant errno.

Extension: `void` simple_object_release_attributes `(simple_object_attributes *attrs)` ¶

  Release all resources associated with attrs.

Extension: `void` simple_object_release_read `(simple_object_read *simple_object)` ¶

  Release all resources associated with simple_object. This does not close the file descriptor.

Extension: `void` simple_object_release_write `(simple_object_write *simple_object)` ¶

  Release all resources associated with simple_object.

Extension: `simple_object_write *` simple_object_start_write `(simple_object_attributes attrs, const char *segment_name, const char **errmsg, int *err)` ¶

  Start creating a new object file using the object file format described in attrs. You must fetch attribute information from an existing object file before you can create a new one. There is currently no support for creating an object file de novo.

  segment_name is only used with Mach-O as found on Darwin aka Mac OS X. The parameter is required on that target. It means that all sections are created within the named segment. It is ignored for other object file formats.

  On error `simple_object_start_write` returns `NULL`, sets `*ERRMSG` to an error message, and sets `*err` to an errno value or `0` if there is no relevant errno.

Extension: `const char *` simple_object_write_add_data `(simple_object_write *simple_object, simple_object_write_section *section, const void *buffer, size_t size, int copy, int *err)` ¶

  Add data buffer/size to section in simple_object. If copy is non-zero, the data will be copied into memory if necessary. If copy is zero, buffer must persist until `simple_object_write_to_file` is called. is released.

  On success this returns `NULL`. On error this returns an error message, and sets `*err` to an errno value or 0 if there is no relevant erro.

Extension: `simple_object_write_section *` simple_object_write_create_section `(simple_object_write *simple_object, const char *name, unsigned int align, const char **errmsg, int *err)` ¶

  Add a section to simple_object. name is the name of the new section. align is the required alignment expressed as the number of required low-order 0 bits (e.g., 2 for alignment to a 32-bit boundary).

  The section is created as containing data, readable, not writable, not executable, not loaded at runtime. The section is not written to the file until `simple_object_write_to_file` is called.

  On error this returns `NULL`, sets `*errmsg` to an error message, and sets `*err` to an errno value or `0` if there is no relevant errno.

Extension: `const char *` simple_object_write_to_file `(simple_object_write *simple_object, int descriptor, int *err)` ¶

  Write the complete object file to descriptor, an open file descriptor. This writes out all the data accumulated by calls to `simple_object_write_create_section` and simple_object_write_add_data.

  This returns `NULL` on success. On error this returns an error message and sets `*err` to an errno value or `0` if there is no relevant errno.

Supplemental: `int` snprintf `(char *buf, size_t n, const char *format, ...)` ¶

  This function is similar to `sprintf`, but it will write to buf at most `n-1` bytes of text, followed by a terminating null byte, for a total of n bytes. On error the return value is -1, otherwise it returns the number of bytes, not including the terminating null byte, that would have been written had n been sufficiently large, regardless of the actual value of n. Note some pre-C99 system libraries do not implement this correctly so users cannot generally rely on the return value if the system version of this function is used.

Extension: `char*` spaces `(int count)` ¶

  Returns a pointer to a memory region filled with the specified number of spaces and null terminated. The returned pointer is valid until at least the next call.

Supplemental: `splay_tree` splay_tree_new_with_typed_alloc `(splay_tree_compare_fn compare_fn, splay_tree_delete_key_fn delete_key_fn, splay_tree_delete_value_fn delete_value_fn, splay_tree_allocate_fn tree_allocate_fn, splay_tree_allocate_fn node_allocate_fn, splay_tree_deallocate_fn deallocate_fn, void * allocate_data)` ¶

  This function creates a splay tree that uses two different allocators tree_allocate_fn and node_allocate_fn to use for allocating the tree itself and its nodes respectively. This is useful when variables of different types need to be allocated with different allocators.

  The splay tree will use compare_fn to compare nodes, delete_key_fn to deallocate keys, and delete_value_fn to deallocate values. Keys and values will be deallocated when the tree is deleted using splay_tree_delete or when a node is removed using splay_tree_remove. splay_tree_insert will release the previously inserted key and value using delete_key_fn and delete_value_fn if the inserted key is already found in the tree.

Extension: `void` stack_limit_increase `(unsigned long pref)` ¶

  Attempt to increase stack size limit to pref bytes if possible.

Supplemental: `char*` stpcpy `(char *dst, const char *src)` ¶

  Copies the string src into dst. Returns a pointer to dst + strlen(src).

Supplemental: `char*` stpncpy `(char *dst, const char *src, size_t len)` ¶

  Copies the string src into dst, copying exactly len and padding with zeros if necessary. If len < strlen(src) then return dst + len, otherwise returns dst + strlen(src).

Supplemental: `int` strcasecmp `(const char *s1, const char *s2)` ¶

  A case-insensitive `strcmp`.

Supplemental: `char*` strchr `(const char *s, int c)` ¶

  Returns a pointer to the first occurrence of the character c in the string s, or `NULL` if not found. If c is itself the null character, the results are undefined.

Supplemental: `char*` strdup `(const char *s)` ¶

  Returns a pointer to a copy of s in memory obtained from `malloc`, or `NULL` if insufficient memory was available.

Replacement: `const char*` strerrno `(int errnum)` ¶

  Given an error number returned from a system call (typically returned in `errno`), returns a pointer to a string containing the symbolic name of that error number, as found in `<errno.h>`.

  If the supplied error number is within the valid range of indices for symbolic names, but no name is available for the particular error number, then returns the string ‘`Error num`’, where num is the error number.

  If the supplied error number is not within the range of valid indices, then returns `NULL`.

  The contents of the location pointed to are only guaranteed to be valid until the next call to `strerrno`.

Supplemental: `char*` strerror `(int errnoval)` ¶

  Maps an `errno` number to an error message string, the contents of which are implementation defined. On systems which have the external variables `sys_nerr` and `sys_errlist`, these strings will be the same as the ones used by `perror`.

  If the supplied error number is within the valid range of indices for the `sys_errlist`, but no message is available for the particular error number, then returns the string ‘`Error num`’, where num is the error number.

  If the supplied error number is not a valid index into `sys_errlist`, returns `NULL`.

  The returned string is only guaranteed to be valid only until the next call to `strerror`.

Supplemental: `int` strncasecmp `(const char *s1, const char *s2)` ¶

  A case-insensitive `strncmp`.

Supplemental: `int` strncmp `(const char *s1, const char *s2, size_t n)` ¶

  Compares the first n bytes of two strings, returning a value as `strcmp`.

Extension: `char*` strndup `(const char *s, size_t n)` ¶

  Returns a pointer to a copy of s with at most n characters in memory obtained from `malloc`, or `NULL` if insufficient memory was available. The result is always NUL terminated.

Supplemental: `size_t` strnlen `(const char *s, size_t maxlen)` ¶

  Returns the length of s, as with `strlen`, but never looks past the first maxlen characters in the string. If there is no ’\0’ character in the first maxlen characters, returns maxlen.

Supplemental: `char*` strrchr `(const char *s, int c)` ¶

  Returns a pointer to the last occurrence of the character c in the string s, or `NULL` if not found. If c is itself the null character, the results are undefined.

Supplemental: `const char *` strsignal `(int signo)` ¶

  Maps an signal number to an signal message string, the contents of which are implementation defined. On systems which have the external variable `sys_siglist`, these strings will be the same as the ones used by `psignal()`.

  If the supplied signal number is within the valid range of indices for the `sys_siglist`, but no message is available for the particular signal number, then returns the string ‘`Signal num`’, where num is the signal number.

  If the supplied signal number is not a valid index into `sys_siglist`, returns `NULL`.

  The returned string is only guaranteed to be valid only until the next call to `strsignal`.

Extension: `const char*` strsigno `(int signo)` ¶

  Given an signal number, returns a pointer to a string containing the symbolic name of that signal number, as found in `<signal.h>`.

  If the supplied signal number is within the valid range of indices for symbolic names, but no name is available for the particular signal number, then returns the string ‘`Signal num`’, where num is the signal number.

  If the supplied signal number is not within the range of valid indices, then returns `NULL`.

  The contents of the location pointed to are only guaranteed to be valid until the next call to `strsigno`.

Supplemental: `char*` strstr `(const char *string, const char *sub)` ¶

  This function searches for the substring sub in the string string, not including the terminating null characters. A pointer to the first occurrence of sub is returned, or `NULL` if the substring is absent. If sub points to a string with zero length, the function returns string.

Supplemental: `double` strtod `(const char *string, char **endptr)` ¶

  This ISO C function converts the initial portion of string to a `double`. If endptr is not `NULL`, a pointer to the character after the last character used in the conversion is stored in the location referenced by endptr. If no conversion is performed, zero is returned and the value of string is stored in the location referenced by endptr.

Extension: `int` strtoerrno `(const char *name)` ¶

  Given the symbolic name of a error number (e.g., `EACCES`), map it to an errno value. If no translation is found, returns 0.

Supplemental: `long int` strtol `(const char *string, char **endptr, int base)` ¶
Supplemental: `unsigned long int` strtoul `(const char *string, char **endptr, int base)` ¶

  The `strtol` function converts the string in string to a long integer value according to the given base, which must be between 2 and 36 inclusive, or be the special value 0. If base is 0, `strtol` will look for the prefixes `0` and `0x` to indicate bases 8 and 16, respectively, else default to base 10. When the base is 16 (either explicitly or implicitly), a prefix of `0x` is allowed. The handling of endptr is as that of `strtod` above. The `strtoul` function is the same, except that the converted value is unsigned.

Supplemental: `long long int` strtoll `(const char *string, char **endptr, int base)` ¶
Supplemental: `unsigned long long int` strtoull `( const char *string, char **endptr, int base)` ¶

  The `strtoll` function converts the string in string to a long long integer value according to the given base, which must be between 2 and 36 inclusive, or be the special value 0. If base is 0, `strtoll` will look for the prefixes `0` and `0x` to indicate bases 8 and 16, respectively, else default to base 10. When the base is 16 (either explicitly or implicitly), a prefix of `0x` is allowed. The handling of endptr is as that of `strtod` above. The `strtoull` function is the same, except that the converted value is unsigned.

Extension: `int` strtosigno `(const char *name)` ¶

  Given the symbolic name of a signal, map it to a signal number. If no translation is found, returns 0.

Function: `int` strverscmp `(const char *s1, const char *s2)` ¶

  The `strverscmp` function compares the string s1 against s2, considering them as holding indices/version numbers. Return value follows the same conventions as found in the `strverscmp` function. In fact, if s1 and s2 contain no digits, `strverscmp` behaves like `strcmp`.

  Basically, we compare strings normally (character by character), until we find a digit in each string - then we enter a special comparison mode, where each sequence of digits is taken as a whole. If we reach the end of these two parts without noticing a difference, we return to the standard comparison mode. There are two types of numeric parts: "integral" and "fractional" (those begin with a ’0’). The types of the numeric parts affect the way we sort them:

  - integral/integral: we compare values as you would expect.
  - fractional/integral: the fractional part is less than the integral one. Again, no surprise.
  - fractional/fractional: the things become a bit more complex. If the common prefix contains only leading zeroes, the longest part is less than the other one; else the comparison behaves normally.

      strverscmp ("no digit", "no digit")
          ⇒ 0    // same behavior as strcmp.
      strverscmp ("item#99", "item#100")
          ⇒ <0   // same prefix, but 99 < 100.
      strverscmp ("alpha1", "alpha001")
          ⇒ >0   // fractional part inferior to integral one.
      strverscmp ("part1_f012", "part1_f01")
          ⇒ >0   // two fractional parts.
      strverscmp ("foo.009", "foo.0")
          ⇒ <0   // idem, but with leading zeroes only.

  This function is especially useful when dealing with filename sorting, because filenames frequently hold indices/version numbers.

Extension: `void` timeval_add `(struct timeval *a, struct timeval *b, struct timeval *result)` ¶

  Adds a to b and stores the result in result.

Extension: `void` timeval_sub `(struct timeval *a, struct timeval *b, struct timeval *result)` ¶

  Subtracts b from a and stores the result in result.

Supplemental: `char*` tmpnam `(char *s)` ¶

  This function attempts to create a name for a temporary file, which will be a valid file name yet not exist when `tmpnam` checks for it. s must point to a buffer of at least `L_tmpnam` bytes, or be `NULL`. Use of this function creates a security risk, and it must not be used in new projects. Use `mkstemp` instead.

Supplemental: `int` unlink_if_ordinary `(const char*)` ¶

  Unlinks the named file, unless it is special (e.g. a device file). Returns 0 when the file was unlinked, a negative value (and errno set) when there was an error deleting the file, and a positive value if no attempt was made to unlink the file because it is special.

Extension: `void` unlock_std_streams `(void)` ¶

  If the OS supports it, ensure that the standard I/O streams, `stdin`, `stdout` and `stderr` are setup to avoid any multi-threaded locking. Otherwise do nothing.

Extension: `void` unlock_stream `(FILE * stream)` ¶

  If the OS supports it, ensure that the supplied stream is setup to avoid any multi-threaded locking. Otherwise leave the `FILE` pointer unchanged. If the stream is `NULL` do nothing.

Extension: `int` vasprintf `(char **resptr, const char *format, va_list args)` ¶

  Like `vsprintf`, but instead of passing a pointer to a buffer, you pass a pointer to a pointer. This function will compute the size of the buffer needed, allocate memory with `malloc`, and store a pointer to the allocated memory in `*resptr`. The value returned is the same as `vsprintf` would return. If memory could not be allocated, minus one is returned and `NULL` is stored in `*resptr`.

Supplemental: `int` vfork `(void)` ¶

  Emulates `vfork` by calling `fork` and returning its value.

Supplemental: `int` vprintf `(const char *format, va_list ap)` ¶
Supplemental: `int` vfprintf `(FILE *stream, const char *format, va_list ap)` ¶
Supplemental: `int` vsprintf `(char *str, const char *format, va_list ap)` ¶

  These functions are the same as `printf`, `fprintf`, and `sprintf`, respectively, except that they are called with a `va_list` instead of a variable number of arguments. Note that they do not call `va_end`; this is the application’s responsibility. In `libiberty` they are implemented in terms of the nonstandard but common function `_doprnt`.

Supplemental: `int` vsnprintf `(char *buf, size_t n, const char *format, va_list ap)` ¶

  This function is similar to `vsprintf`, but it will write to buf at most `n-1` bytes of text, followed by a terminating null byte, for a total of n bytes. On error the return value is -1, otherwise it returns the number of characters that would have been printed had n been sufficiently large, regardless of the actual value of n. Note some pre-C99 system libraries do not implement this correctly so users cannot generally rely on the return value if the system version of this function is used.

Supplemental: `int` waitpid `(int pid, int *status, int)` ¶

  This is a wrapper around the `wait` function. Any “special” values of pid depend on your implementation of `wait`, as does the return value. The third argument is unused in `libiberty`.

Extension: `int` writeargv `(char * const *argv, FILE *file)` ¶

  Write each member of ARGV, handling all necessary quoting, to the file named by FILE, separated by whitespace. Return 0 on success, non-zero if an error occurred while writing to FILE.

Replacement: `char*` xasprintf `(const char *format, ...)` ¶

  Print to allocated string without fail. If `xasprintf` fails, this will print a message to `stderr` (using the name set by `xmalloc_set_program_name`, if any) and then call `xexit`.

Function: `int` xatexit `(void (*fn) (void))` ¶

  Behaves as the standard `atexit` function, but with no limit on the number of registered functions. Returns 0 on success, or −1 on failure. If you use `xatexit` to register functions, you must use `xexit` to terminate your program.

Replacement: `void*` xcalloc `(size_t nelem, size_t elsize)` ¶

  Allocate memory without fail, and set it to zero. This routine functions like `calloc`, but will behave the same as `xmalloc` if memory cannot be found.

Replacement: `void` xexit `(int code)` ¶

  Terminates the program. If any functions have been registered with the `xatexit` replacement function, they will be called first. Termination is handled via the system’s normal `exit` call.

Replacement: `void*` xmalloc `(size_t)` ¶

  Allocate memory without fail. If `malloc` fails, this will print a message to `stderr` (using the name set by `xmalloc_set_program_name`, if any) and then call `xexit`. Note that it is therefore safe for a program to contain `#define malloc xmalloc` in its source.

Replacement: `void` xmalloc_failed `(size_t)` ¶

  This function is not meant to be called by client code, and is listed here for completeness only. If any of the allocation routines fail, this function will be called to print an error message and terminate execution.

Replacement: `void` xmalloc_set_program_name `(const char *name)` ¶

  You can use this to set the name of the program used by `xmalloc_failed` when printing a failure message.

Replacement: `void*` xmemdup `(void *input, size_t copy_size, size_t alloc_size)` ¶

  Duplicates a region of memory without fail. First, alloc_size bytes are allocated, then copy_size bytes from input are copied into it, and the new memory is returned. If fewer bytes are copied than were allocated, the remaining memory is zeroed.

Replacement: `void*` xrealloc `(void *ptr, size_t size)` ¶

  Reallocate memory without fail. This routine functions like `realloc`, but will behave the same as `xmalloc` if memory cannot be found.

Replacement: `char*` xstrdup `(const char *s)` ¶

  Duplicates a character string without fail, using `xmalloc` to obtain memory.

Replacement: `char*` xstrerror `(int errnum)` ¶

  Behaves exactly like the standard `strerror` function, but will never return a `NULL` pointer.

Replacement: `char*` xstrndup `(const char *s, size_t n)` ¶

  Returns a pointer to a copy of s with at most n characters without fail, using `xmalloc` to obtain memory. The result is always NUL terminated.

Replacement: `char*` xvasprintf `(const char *format, va_list args)` ¶

  Print to allocated string without fail. If `xvasprintf` fails, this will print a message to `stderr` (using the name set by `xmalloc_set_program_name`, if any) and then call `xexit`.