asprintf(3)                Library Functions Manual                asprintf(3)

NAME
       asprintf, vasprintf - print to allocated string

LIBRARY
       Standard C library (libc, -lc)

SYNOPSIS
       #define _GNU_SOURCE         /* See feature_test_macros(7) */
       #include <stdio.h>

       int asprintf(char **restrict strp, const char *restrict fmt, ...);
       int vasprintf(char **restrict strp, const char *restrict fmt,
                     va_list ap);

DESCRIPTION
       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.

RETURN VALUE
       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.

ATTRIBUTES
       For an explanation of the terms used in this section, see
       attributes(7).

       +-------------------------------------+---------------+----------------+
       |Interface                            | Attribute     | Value          |
       +-------------------------------------+---------------+----------------+
       |asprintf (), vasprintf ()            | Thread safety | MT-Safe locale |
       +-------------------------------------+---------------+----------------+
VERSIONS
       The FreeBSD implementation sets strp to NULL on error.

STANDARDS
       GNU, BSD.

SEE ALSO
       free(3), malloc(3), printf(3)

Linux man-pages 6.7               2023-10-31                       asprintf(3)