GETLINE(3) BSD Library Functions Manual GETLINE(3)NAME
getdelim, getline — get a line from a stream
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#define _WITH_GETLINE
#include <stdio.h>
ssize_t
getdelim(char ** restrict linep, size_t * restrict linecapp,
int delimiter, FILE * restrict stream);
ssize_t
getline(char ** restrict linep, size_t * restrict linecapp,
FILE * restrict stream);
DESCRIPTION
The getdelim() function reads a line from stream, delimited by the char‐
acter delimiter. The getline() function is equivalent to getdelim() with
the newline character as the delimiter. The delimiter character is
included as part of the line, unless the end of the file is reached. The
caller may provide a pointer to a malloc buffer for the line in *linep,
and the capacity of that buffer in *linecapp; if *linecapp is 0, then
*linep is treated as NULL. These functions may expand the buffer as
needed, as if via realloc(), and update *linep and *linecapp accordingly.
RETURN VALUES
The getdelim() and getline() functions return the number of characters
written, excluding the terminating NUL. The value -1 is returned if an
error occurs, or if end-of-file is reached.
EXAMPLES
The following code fragment reads lines from a file and writes them to
standard output. The fwrite() function is used in case the line contains
embedded NUL characters.
char *line = NULL;
size_t linecap = 0;
ssize_t linelen;
while ((linelen = getline(&line, &linecap, fp)) > 0)
fwrite(line, linelen, 1, stdout);
COMPATIBILITY
Many application writers used the name getline before the getline() func‐
tion was introduced in IEEE Std 1003.1 (“POSIX.1”), so a prototype is not
provided by default in order to avoid compatibility problems. Applica‐
tions that wish to use the getline() function described herein should
either request a strict IEEE Std 1003.1-2008 (“POSIX.1”) environment by
defining the macro _POSIX_C_SOURCE to the value 200809 or greater, or by
defining the macro _WITH_GETLINE, prior to the inclusion of <stdio.h>.
For compatibility with GNU libc, defining either _BSD_SOURCE or
_GNU_SOURCE prior to the inclusion of <stdio.h> will also make getline()
available.
ERRORS
These functions may fail if:
[EINVAL] Either linep or linecapp is NULL.
[EOVERFLOW] No delimiter was found in the first SSIZE_MAX charac‐
ters.
These functions may also fail for any of the errors specified for fgets()
and malloc().
SEE ALSOfgetln(3), fgets(3), malloc(3)STANDARDS
The getdelim() and getline() functions conform to IEEE Std 1003.1-2008
(“POSIX.1”).
HISTORY
These routines first appeared in DragonFly 2.3.
BUGS
There are no wide character versions of getdelim() or getline().
BSD March 29, 2009 BSD