asprintf3
Print to allocated string
Usage
#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);
Library
Standard C library (libc, -lc)
Overview
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). On error, -1 is returned, errno is set to indicate the error, and the contents of strp are undefined.
Errors
See sprintf(3) and malloc(3).
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.
Releases
16 releases since Debian 2.0 (Hamm); the text changed 15 times.