trusty (3) getdelim.3.gz

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)):

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

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 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 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 ('\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.

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)

COLOPHON

       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 http://www.kernel.org/doc/man-pages/.