GETLINE(3) Linux Programmer's Manual GETLINE(3)
getline, getdelim - delimited string input
#define _GNU_SOURCE
#include <stdio.h>
ssize_t getline(char **lineptr, size_t *n, FILE *stream);
ssize_t getdelim(char **lineptr, size_t *n, int delim, FILE *stream);
getline() reads an entire line from stream, storing the address of the
buffer containing the text into *lineptr. The buffer is null-termi-
nated and includes the newline character, if one was found.
If *lineptr is NULL, then getline() will allocate a buffer for storing
the line, which should be freed by the user program. (The value in *n
is ignored.)
Alternatively, before calling getline(), *lineptr can contain a pointer
to a malloc(3)-allocated buffer *n bytes in size. If the buffer is not
large enough to hold the line, getline() resizes it with realloc(3),
updating *lineptr and *n as necessary.
In either case, on a successful call, *lineptr and *n will be updated
to reflect the buffer address and allocated size respectively.
getdelim() works like getline(), except a line delimiter other than
newline can be specified as the delimiter argument. As with getline(),
a delimiter character is not added if one was not present in the input
before end of file was reached.
On success, getline() and getdelim() return the number of characters
read, including the delimiter character, but not including the termi-
nating null byte. This value can be used to handle embedded null bytes
in the line read.
Both functions return -1 on failure to read a line (including end of
file condition).
EINVAL Bad arguments (n or lineptr is NULL, or stream is not valid).
Both getline() and getdelim() are GNU extensions. They are available
since libc 4.6.27.
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
int
main(void)
{
FILE * fp;
char * line = NULL;
size_t len = 0;
ssize_t read;
fp = fopen("/etc/motd", "r");
if (fp == NULL)
exit(EXIT_FAILURE);
while ((read = getline(&line, &len, fp)) != -1) {
printf("Retrieved line of length %zu :\n", read);
printf("%s", line);
}
if (line)
free(line);
exit(EXIT_SUCCESS);
}
read(2), fgets(3), fopen(3), fread(3), gets(3), scanf(3), fea-
ture_test_macros(7)
This page is part of release 3.05 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
GNU 2006-05-17 GETLINE(3)