asprintf(3) - Linux manual page (original) (raw)

asprintf(3) Library Functions Manual asprintf(3)

NAME top

   asprintf, vasprintf - print to allocated string

LIBRARY top

   Standard C library (_libc_, _-lc_)

SYNOPSIS top

   **#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 top

   The functions **asprintf**() and **vasprintf**() are analogs of [sprintf(3)](../man3/sprintf.3.html)
   and [vsprintf(3)](../man3/vsprintf.3.html), 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)](../man3/free.3.html) to release the allocated storage when
   it is no longer needed.

RETURN VALUE top

   When successful, these functions return the number of bytes
   printed, just like [sprintf(3)](../man3/sprintf.3.html).  If memory allocation wasn't
   possible, or some other error occurs, these functions will return
   -1, and the contents of _strp_ are undefined.

ATTRIBUTES top

   For an explanation of the terms used in this section, see
   [attributes(7)](../man7/attributes.7.html).
   ┌───────────────────────────────┬───────────────┬────────────────┐
   │ **Interface** │ **Attribute** │ **Value** │
   ├───────────────────────────────┼───────────────┼────────────────┤
   │ **asprintf**(), **vasprintf**()       │ Thread safety │ MT-Safe locale │
   └───────────────────────────────┴───────────────┴────────────────┘

VERSIONS top

   The FreeBSD implementation sets _strp_ to NULL on error.

STANDARDS top

   GNU, BSD.

SEE ALSO top

   [free(3)](../man3/free.3.html), [malloc(3)](../man3/malloc.3.html), [printf(3)](../man3/printf.3.html)

COLOPHON top

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Linux man-pages 6.10 2024-07-23 asprintf(3)

Pages that refer to this page:lttng_ust_tracef(3), lttng_ust_tracelog(3), printf(3), printf.h(3head)