asprintf, aswprintf, vasprintf, vaswprintf
| Defined in header <stdio.h>
|
||
| int asprintf( char **restrict strp, const char *restrict fmt, ... ); |
(1) | (dynamic memory TR) |
| int aswprintf( wchar_t **restrict strp, const wchar_t *restrict fmt, ... ); |
(2) | (dynamic memory TR) |
| int vasprintf( char **restrict strp, const char *restrict fmt, va_list arg ); |
(3) | (dynamic memory TR) |
| int vaswprintf( wchar_t **restrict strp, const wchar_t *restrict fmt, va_list arg ); |
(4) | (dynamic memory TR) |
arg, which shall be initialized by the va_start macro (and possibly subsequent va_arg calls).Parameters
Return value
The number of characters written, just like MYMEMORY WARNING: YOU USED ALL AVAILABLE FREE TRANSLATIONS FOR TODAY. NEXT AVAILABLE IN 11 HOURS 42 MINUTES 28 SECONDS VISIT HTTPS://MYMEMORY.TRANSLATED.NET/DOC/USAGELIMITS.PHP TO TRANSLATE MORE (1), MYMEMORY WARNING: YOU USED ALL AVAILABLE FREE TRANSLATIONS FOR TODAY. NEXT AVAILABLE IN 11 HOURS 42 MINUTES 27 SECONDS VISIT HTTPS://MYMEMORY.TRANSLATED.NET/DOC/USAGELIMITS.PHP TO TRANSLATE MORE (2), MYMEMORY WARNING: YOU USED ALL AVAILABLE FREE TRANSLATIONS FOR TODAY. NEXT AVAILABLE IN 11 HOURS 42 MINUTES 25 SECONDS VISIT HTTPS://MYMEMORY.TRANSLATED.NET/DOC/USAGELIMITS.PHP TO TRANSLATE MORE (3), or MYMEMORY WARNING: YOU USED ALL AVAILABLE FREE TRANSLATIONS FOR TODAY. NEXT AVAILABLE IN 11 HOURS 42 MINUTES 24 SECONDS VISIT HTTPS://MYMEMORY.TRANSLATED.NET/DOC/USAGELIMITS.PHP TO TRANSLATE MORE (4), respectively. If memory allocation wasn't possible, or some other error occurs, these functions will return -1, and the contents of strp is undefined.
Notes
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.
The vasprintf and vaswprintf functions do not invoke the va_end macro.
Example
MYMEMORY WARNING: YOU USED ALL AVAILABLE FREE TRANSLATIONS FOR TODAY. NEXT AVAILABLE IN 11 HOURS 42 MINUTES 23 SECONDS VISIT HTTPS://MYMEMORY.TRANSLATED.NET/DOC/USAGELIMITS.PHP TO TRANSLATE MORE
#include <stdio.h> #include <stdlib.h> #include <stdarg.h> void test(const char *fmt, ...) { char* dyn_buf; MYMEMORY WARNING: YOU USED ALL AVAILABLE FREE TRANSLATIONS FOR TODAY. NEXT AVAILABLE IN 11 HOURS 42 MINUTES 22 SECONDS VISIT HTTPS://MYMEMORY.TRANSLATED.NET/DOC/USAGELIMITS.PHP TO TRANSLATE MORE("Demo asprintf:\n"); const int written_1 = asprintf(&dyn_buf, "%s", fmt); MYMEMORY WARNING: YOU USED ALL AVAILABLE FREE TRANSLATIONS FOR TODAY. NEXT AVAILABLE IN 11 HOURS 42 MINUTES 20 SECONDS VISIT HTTPS://MYMEMORY.TRANSLATED.NET/DOC/USAGELIMITS.PHP TO TRANSLATE MORE("dyn_buf: \"%s\"; %i chars were written\n", dyn_buf, written_1); MYMEMORY WARNING: YOU USED ALL AVAILABLE FREE TRANSLATIONS FOR TODAY. NEXT AVAILABLE IN 11 HOURS 42 MINUTES 19 SECONDS VISIT HTTPS://MYMEMORY.TRANSLATED.NET/DOC/USAGELIMITS.PHP TO TRANSLATE MORE(dyn_buf); MYMEMORY WARNING: YOU USED ALL AVAILABLE FREE TRANSLATIONS FOR TODAY. NEXT AVAILABLE IN 11 HOURS 42 MINUTES 18 SECONDS VISIT HTTPS://MYMEMORY.TRANSLATED.NET/DOC/USAGELIMITS.PHP TO TRANSLATE MORE("Demo vasprintf:\n"); va_list args; va_start(args, fmt); const int written_2 = vasprintf(&dyn_buf, fmt, args); va_end(args); MYMEMORY WARNING: YOU USED ALL AVAILABLE FREE TRANSLATIONS FOR TODAY. NEXT AVAILABLE IN 11 HOURS 42 MINUTES 17 SECONDS VISIT HTTPS://MYMEMORY.TRANSLATED.NET/DOC/USAGELIMITS.PHP TO TRANSLATE MORE("dyn_buf: \"%s\"; %i chars were written\n", dyn_buf, written_2); MYMEMORY WARNING: YOU USED ALL AVAILABLE FREE TRANSLATIONS FOR TODAY. NEXT AVAILABLE IN 11 HOURS 42 MINUTES 15 SECONDS VISIT HTTPS://MYMEMORY.TRANSLATED.NET/DOC/USAGELIMITS.PHP TO TRANSLATE MORE(dyn_buf); } int main(void) { test("Testing... %d, %d, %d", 1, 2, 3); }
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Demo asprintf: dyn_buf: "Testing... %d, %d, %d"; 21 chars were written Demo vasprintf: dyn_buf: "Testing... 1, 2, 3"; 18 chars were written