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ASPRINTF(3) Linux Programmer's Manual ASPRINTF(3)

NAME

     asprintf, vasprintf - print to allocated string

SYNOPSIS

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

     int asprintf(char **strp, const char *fmt, ...);

     int vasprintf(char **strp, const char *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).

     allbox;  lbw23  lb  lb l l l.  Interface Attribute Value T{ asprintf(),
     vasprintf() T}   Thread safety  MT-Safe locale

CONFORMING TO

     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.

SEE ALSO

     free(3), malloc(3), printf(3)

COLOPHON

     This page is part of release 4.16 of the Linux  man-pages  project.   A
     description  of  the project, information about reporting bugs, and the
     latest    version    of    this    page,    can     be     found     at
     https://www.kernel.org/doc/man-pages/.

GNU 2017-09-15 ASPRINTF(3)