GETLINE(3) Linux Programmer's Manual GETLINE(3)NAME
getline, getdelim - delimited string input
SYNOPSIS
#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);
DESCRIPTIONgetline() 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. Alternatively,
before calling getline(), *lineptr can contain a pointer to a mal‐
loc()-allocated buffer *n bytes in size. If the buffer is not large
enough to hold the line, getline() resizes it with realloc(), 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 allo‐
cated 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.
RETURN VALUE
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).
ERRORS
EINVAL Bad parameters (n or lineptr is NULL, or stream is not valid).
EXAMPLE
#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);
return EXIT_SUCCESS;
}
CONFORMING TO
Both getline() and getdelim() are GNU extensions. They are available
since libc 4.6.27.
SEE ALSOread(2), fgets(3), fopen(3), fread(3), gets(3), scanf(3)GNU 2006-05-17 GETLINE(3)
