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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ATTRIBUTES | CONFORMING TO | SEE ALSO | COLOPHON |
ASPRINTF(3) Linux Programmer's Manual ASPRINTF(3)
asprintf, vasprintf - print to allocated string
#define _GNU_SOURCE /* See feature_test_macros(7) */
#include <stdio.h>
int asprintf(char **strp, const char *fmt, ...);
int vasprintf(char **strp, const char *fmt, va_list ap);
The functions asprintf() and vasprintf() are analogs of sprintf(3)
and vsprintf(3), except that they allocate a string large enough to
hold the output including the terminating null byte ('\0'), and
return a pointer to it via the first argument. This pointer should
be passed to free(3) to release the allocated storage when it is no
longer needed.
When successful, these functions return the number of bytes printed,
just like sprintf(3). If memory allocation wasn't possible, or some
other error occurs, these functions will return -1, and the contents
of strp are undefined.
For an explanation of the terms used in this section, see
attributes(7).
┌────────────────────────┬───────────────┬────────────────┐
│Interface │ Attribute │ Value │
├────────────────────────┼───────────────┼────────────────┤
│asprintf(), vasprintf() │ Thread safety │ MT-Safe locale │
└────────────────────────┴───────────────┴────────────────┘
These functions are GNU extensions, not in C or POSIX. They are also
available under *BSD. The FreeBSD implementation sets strp to NULL
on error.
free(3), malloc(3), printf(3)
This page is part of release 4.12 of the Linux man-pages project. A
description of the project, information about reporting bugs, and the
latest version of this page, can be found at
https://www.kernel.org/doc/man-pages/.
GNU 2015-04-19 ASPRINTF(3)
Pages that refer to this page: printf(3), tracef(3), tracelog(3)