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GETDELIM(3) Library Functions Manual GETDELIM(3)

getdelim, getlineread a delimited record from a stream

#include <stdio.h>

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

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

The () function reads from the stream until it encounters a character matching delimiter, storing the input in *lineptr. The buffer is NUL-terminated and includes the delimiter. 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. () will realloc(3) *lineptr as necessary, updating *n to reflect the new size. It is the responsibility of the caller to free(3) *lineptr when it is no longer needed. Even when it fails, getdelim() may update *lineptr.

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

The getdelim() and getline() functions return the number of characters read, including the delimiter. 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.

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))
	err(1, "getline");

lineptr or n is a NULL pointer.
More than SSIZE_MAX characters were read without encountering 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).

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

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

These functions were ported from NetBSD to OpenBSD 5.2.

October 17, 2017 OpenBSD-6.7