GETLINE(3)                                          Linux Programmer's Manual                                         GETLINE(3)



NAME
       getline, getdelim - delimited string input

SYNOPSIS
       #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);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       Before glibc 2.10:
       getline(), getdelim(): _GNU_SOURCE

       Since glibc 2.10:
       getline(), getdelim(): _POSIX_C_SOURCE >= 200809L || _XOPEN_SOURCE >= 700

DESCRIPTION
       getline()  reads  an  entire  line from stream, storing the address of the buffer containing the text into *lineptr.  The
       buffer is null-terminated 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  pro-
       gram.  (In this case, 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.

RETURN VALUE
       On  success,  getline()  and  getdelim() return the number of characters read, including the delimiter character, but not
       including the terminating 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 arguments (n or lineptr is NULL, or stream is not valid).

VERSIONS
       These functions are available since libc 4.6.27.

CONFORMING TO
       Both getline() and getdelim() were originally GNU extensions.  They were standardized in POSIX.1-2008.

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);
           }

           free(line);
           exit(EXIT_SUCCESS);
       }

SEE ALSO
       read(2), fgets(3), fopen(3), fread(3), gets(3), scanf(3), feature_test_macros(7)

COLOPHON
       This page is part of release 3.25 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                                                        2010-06-12                                                 GETLINE(3)