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 character 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 malloced buffer for the line in *linep, and the capacity of that buffer in *linecapp. These functions expand the buffer as needed, as if via realloc(). If linep points to a NULL pointer, a new buffer will be allocated. In either case, *linep and *linecapp will be updated accordingly.

RETURN VALUES

The getdelim() and getline() functions return the number of characters stored in the buffer, excluding the terminating NUL character. 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() function was introduced in IEEE Std 1003.1 (“POSIX.1”), so a prototype is not provided by default in order to avoid compatibility problems. Applications 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 characters.

These functions may also fail due to any of the errors specified for fgets() and malloc().

SEE ALSO

fgetln(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 FreeBSD 8.0.

BUGS

There are no wide character versions of getdelim() or getline().