getline(3) - NetBSD Manual Pages

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GETDELIM(3)             NetBSD Library Functions Manual            GETDELIM(3)


NAME

     getdelim, getline -- read a delimited record from a stream


LIBRARY

     Standard C Library (libc, -lc)


SYNOPSIS

     #include <stdio.h>

     ssize_t
     getdelim(char ** restrict lineptr, size_t * restrict n, int delimiter,
         FILE * restrict stream);

     ssize_t
     getline(char ** restrict lineptr, size_t * restrict n,
         FILE * restrict stream);


DESCRIPTION

     The getdelim() function reads from the stream until it encounters a char-
     acter matching delimiter or EOF, storing the input in *lineptr.  The
     buffer is NUL-terminated and includes the delimiter, if one was found.
     The delimiter character must be representable as an unsigned char.

     If *n is non-zero, then *lineptr must be pre-allocated to at least *n
     bytes.  The buffer should be allocated dynamically; it must be possible
     to free(3) *lineptr.  getdelim() ensures that *lineptr is large enough to
     hold the input, updating *n to reflect the new size.

     The getline() function is equivalent to getdelim() with delimiter set to
     the newline character.


RETURN VALUES

     The getdelim() and getline() functions return the number of characters
     read, including the delimiter if one was found.  If no characters were
     read and the stream is at end-of-file, the functions return -1.  If an
     error occurs, the functions return -1 and the global variable errno is
     set to indicate the error.

     The functions do not distinguish between end-of-file and error, and
     callers must use feof(3) and ferror(3) to determine which occurred.


EXAMPLES

     The following code fragment reads lines from a file and writes them to
     standard output.

           char *line = NULL;
           size_t linesize = 0;
           ssize_t linelen;

           while ((linelen = getline(&line, &linesize, fp)) != -1)
                   fwrite(line, linelen, 1, stdout);

           if (ferror(fp))
                   perror("getline");


ERRORS

     [EINVAL]     lineptr or n is a NULL pointer.

     [EOVERFLOW]  More than SSIZE_MAX characters were read without encounter-
                  ing the delimiter.

     The getdelim() and getline() functions may also fail and set errno for
     any of the errors specified in the routines fflush(3), malloc(3),
     read(2), stat(2), or realloc(3).


SEE ALSO

     ferror(3), fgets(3), fopen(3), strlen(3)


STANDARDS

     The getdelim() and getline() functions conform to IEEE Std 1003.1-2008
     (``POSIX.1'').


NOTES

     The getdelim() and getline() functions can return results that include
     NUL characters, which can cause the apparent length reported by strlen(3)
     to be less than the true length reported by the return values of the
     functions.

NetBSD 9.2                    September 15, 2014                    NetBSD 9.2