The following procedures read or write characters and strings from and
to open files. The external encoding of the files is assumed to be
UTF-8. Since Algol 68 chars are UCS-4, this means that
reading or writing a character may involve reading or writing more
than one byte, depending on the particular Unicode code points
involved.
= (char c) char ¶Write the given character to the standard output. This procedure
yields c in case the character got successfully written, or
eof char otherwise.
= (string str) void ¶Write the given string to the standard output.
= (int fd, char c) int ¶Write given character c to the file with descriptor fd.
This procedure yields c on success, or eof char on
error.
= (int fd, string str) int ¶Write the given string str to the file with descriptor
fd. This procedure yields the number of bytes written on
success, or 0 on error.
= char ¶Read a character from the standard input. This procedure yields the
read character in case the character got successfully read, or
eof char otherwise.
= (int n) ref string ¶Read a string composed of n characters from the standard input
and yield a reference to it. If n is bigger than zero then
characters get read until either n characters have been read or
the end of line is reached. If n is zero or negative then
characters get read until either a new line character is read or the
end of line is reached.
= (int fd) int ¶Read a character from the file with descriptor fd. This
procedure yields the read character in case a valid Unicode character
got successfully read. If an unrecognizable or unknown character is
found then this procedure yields replacement char. In case of
end of file this procedure yields eof char.
= (int fd, int n) ref string ¶Read a string from the file with descriptor fd and yield a
reference to it. If n is bigger than zero then characters get
read until either n characters have been read or the end of
line is reached. If n is zero or negative then characters get
read until either a new line character is read or the end of line is
reached.