Simple Output (The GNU C Library)

### 12.7 Simple Output by Characters or Lines ¶

This section describes functions for performing character- and line-oriented output.

These narrow stream functions are declared in the header file `stdio.h` and the wide stream functions in `wchar.h`.

Function: `int` fputc `(int c, FILE *stream)` ¶

  Preliminary: | MT-Safe | AS-Unsafe corrupt | AC-Unsafe corrupt lock | See POSIX Safety Concepts.

  The `fputc` function converts the character c to type `unsigned char`, and writes it to the stream stream. `EOF` is returned if a write error occurs; otherwise the character c is returned.

Function: `wint_t` fputwc `(wchar_t wc, FILE *stream)` ¶

  Preliminary: | MT-Safe | AS-Unsafe corrupt | AC-Unsafe corrupt lock | See POSIX Safety Concepts.

  The `fputwc` function writes the wide character wc to the stream stream. `WEOF` is returned if a write error occurs; otherwise the character wc is returned.

Function: `int` fputc_unlocked `(int c, FILE *stream)` ¶

  Preliminary: | MT-Safe race:stream | AS-Unsafe corrupt | AC-Unsafe corrupt | See POSIX Safety Concepts.

  The `fputc_unlocked` function is equivalent to the `fputc` function except that it does not implicitly lock the stream.

Function: `wint_t` fputwc_unlocked `(wchar_t wc, FILE *stream)` ¶

  Preliminary: | MT-Safe race:stream | AS-Unsafe corrupt | AC-Unsafe corrupt | See POSIX Safety Concepts.

  The `fputwc_unlocked` function is equivalent to the `fputwc` function except that it does not implicitly lock the stream.

  This function is a GNU extension.

Function: `int` putc `(int c, FILE *stream)` ¶

  Preliminary: | MT-Safe | AS-Unsafe corrupt | AC-Unsafe corrupt lock | See POSIX Safety Concepts.

  This is just like `fputc`, except that it may be implemented as a macro and may evaluate the stream argument more than once. Therefore, stream should never be an expression with side-effects.

Function: `wint_t` putwc `(wchar_t wc, FILE *stream)` ¶

  Preliminary: | MT-Safe | AS-Unsafe corrupt | AC-Unsafe corrupt lock | See POSIX Safety Concepts.

  This is just like `fputwc`, except that it may be implemented as a macro and may evaluate the stream argument more than once. Therefore, stream should never be an expression with side-effects.

Function: `int` putc_unlocked `(int c, FILE *stream)` ¶

  Preliminary: | MT-Safe race:stream | AS-Unsafe corrupt | AC-Unsafe corrupt | See POSIX Safety Concepts.

  The `putc_unlocked` function is equivalent to the `putc` function except that it does not implicitly lock the stream. Like `putc`, it may be implemented as a macro and may evaluate the stream argument more than once. Therefore, stream should not be an expression with side-effects.

Function: `wint_t` putwc_unlocked `(wchar_t wc, FILE *stream)` ¶

  Preliminary: | MT-Safe race:stream | AS-Unsafe corrupt | AC-Unsafe corrupt | See POSIX Safety Concepts.

  The `putwc_unlocked` function is equivalent to the `putwc` function except that it does not implicitly lock the stream.

  This function is a GNU extension.

Function: `int` putchar `(int c)` ¶

  Preliminary: | MT-Safe | AS-Unsafe corrupt | AC-Unsafe corrupt lock | See POSIX Safety Concepts.

  The `putchar` function is equivalent to `putc` with `stdout` as the value of the stream argument.

Function: `wint_t` putwchar `(wchar_t wc)` ¶

  Preliminary: | MT-Safe | AS-Unsafe corrupt | AC-Unsafe corrupt lock | See POSIX Safety Concepts.

  The `putwchar` function is equivalent to `putwc` with `stdout` as the value of the stream argument.

Function: `int` putchar_unlocked `(int c)` ¶

  Preliminary: | MT-Unsafe race:stdout | AS-Unsafe corrupt | AC-Unsafe corrupt | See POSIX Safety Concepts.

  The `putchar_unlocked` function is equivalent to the `putchar` function except that it does not implicitly lock the stream.

Function: `wint_t` putwchar_unlocked `(wchar_t wc)` ¶

  Preliminary: | MT-Unsafe race:stdout | AS-Unsafe corrupt | AC-Unsafe corrupt | See POSIX Safety Concepts.

  The `putwchar_unlocked` function is equivalent to the `putwchar` function except that it does not implicitly lock the stream.

  This function is a GNU extension.

Function: `int` fputs `(const char *s, FILE *stream)` ¶

  Preliminary: | MT-Safe | AS-Unsafe corrupt | AC-Unsafe corrupt lock | See POSIX Safety Concepts.

  The function `fputs` writes the string s to the stream stream. The terminating null character is not written. This function does not add a newline character, either. It outputs only the characters in the string.

  This function returns `EOF` if a write error occurs, and otherwise a non-negative value.

  For example:

      fputs ("Are ", stdout);
      fputs ("you ", stdout);
      fputs ("hungry?\n", stdout);

  outputs the text ‘`Are you hungry?`’ followed by a newline.

Function: `int` fputws `(const wchar_t *ws, FILE *stream)` ¶

  Preliminary: | MT-Safe | AS-Unsafe corrupt | AC-Unsafe corrupt lock | See POSIX Safety Concepts.

  The function `fputws` writes the wide character string ws to the stream stream. The terminating null character is not written. This function does not add a newline character, either. It outputs only the characters in the string.

  This function returns `WEOF` if a write error occurs, and otherwise a non-negative value.

Function: `int` fputs_unlocked `(const char *s, FILE *stream)` ¶

  Preliminary: | MT-Safe race:stream | AS-Unsafe corrupt | AC-Unsafe corrupt | See POSIX Safety Concepts.

  The `fputs_unlocked` function is equivalent to the `fputs` function except that it does not implicitly lock the stream.

  This function is a GNU extension.

Function: `int` fputws_unlocked `(const wchar_t *ws, FILE *stream)` ¶

  Preliminary: | MT-Safe race:stream | AS-Unsafe corrupt | AC-Unsafe corrupt | See POSIX Safety Concepts.

  The `fputws_unlocked` function is equivalent to the `fputws` function except that it does not implicitly lock the stream.

  This function is a GNU extension.

Function: `int` puts `(const char *s)` ¶

  Preliminary: | MT-Safe | AS-Unsafe corrupt | AC-Unsafe lock corrupt | See POSIX Safety Concepts.

  The `puts` function writes the string s to the stream `stdout` followed by a newline. The terminating null character of the string is not written. (Note that `fputs` does not write a newline as this function does.)

  `puts` is the most convenient function for printing simple messages. For example:

      puts ("This is a message.");

  outputs the text ‘`This is a message.`’ followed by a newline.

Function: `int` putw `(int w, FILE *stream)` ¶

  Preliminary: | MT-Safe | AS-Unsafe corrupt | AC-Unsafe lock corrupt | See POSIX Safety Concepts.

  This function writes the word w (that is, an `int`) to stream. It is provided for compatibility with SVID, but we recommend you use `fwrite` instead (see Block Input/Output).