Name
asprintf, vasprintf - print to allocated string Library
Standard C library ( libc ", " -lc ) Synopsis
"#define(7)_GNU_SOURCE" " /* See feature_test_macros */" #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 ('\e0'), 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). allbox; lbx lb lb | Interface | Attribute | Value |
T{ asprintf() vasprintf() | T} | Thread safety | MT-Safe locale |
Versions
The FreeBSD implementation sets strp to NULL on error.