#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)):

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

       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.   (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 that a line delimiter other
       than newline can be specified as the delimiter argument.  As with  get-
       line(),  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 ('\0').  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).  In the event of an error, errno is  set  to  indicate
       the cause.

       EINVAL Bad arguments (n or lineptr is NULL, or stream is not valid).

       These functions are available since libc 4.6.27.

           FILE *fp;
           char *line = NULL;
           size_t len = 0;
           ssize_t read;

           fp = fopen("/etc/motd", "r");
           if (fp == NULL)

           while ((read = getline(&line, &len, fp)) != -1) {
               printf("Retrieved line of length %zu :\n", read);
               printf("%s", line);


       read(2), fgets(3), fopen(3), fread(3), gets(3), scanf(3)

       This page is part of release 3.54 of the Linux  man-pages  project.   A
       description  of  the project, and information about reporting bugs, can
       be found at

GNU                               2013-04-19                        GETLINE(3)
Man Pages Copyright Respective Owners. Site Copyright (C) 1994 - 2019 Hurricane Electric. All Rights Reserved.