NAME
vasprintf vdprintf
vfprintf vprintf
vsnprintf vsprintf —
format output of a stdarg argument list
SYNOPSIS
#include
<stdarg.h>
#include <stdio.h>
[CX] int vasprintf(char **restrict ptr, const char *restrict format,
va_list ap);
int vdprintf(int fildes, const char *restrict format, va_list ap);
int vfprintf(FILE *restrict stream, const char *restrict format,
va_list ap);
int vprintf(const char *restrict format, va_list ap);
int vsnprintf(char *restrict s, size_t n, const char *restrict format,
va_list ap);
int vsprintf(char *restrict s, const char *restrict format, va_list ap);
DESCRIPTION
[CX] The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the requirements described here and the ISO C standard is unintentional. This volume of POSIX.1-2024 defers to the ISO C standard.
The [CX] vasprintf (),
vdprintf (), vfprintf (),
vprintf (), vsnprintf (), and
vsprintf () functions shall be equivalent to the
[CX] asprintf(3),
dprintf(3), fprintf(3),
printf(3), snprintf(3), and
sprintf(3) functions respectively, except that instead of
being called with a variable number of arguments, they are called with an
argument list as defined by <stdarg.h>.
These functions shall not invoke the va_end macro. As these functions invoke the va_arg macro, the value of ap after the return is unspecified.
RETURN VALUE
Refer to fprintf(3).
ERRORS
Refer to fprintf(3).
EXAMPLES
None.
APPLICATION USAGE
Applications using these functions should call va_end ( ap) afterwards to clean up.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
XBD <stdarg.h>, <stdio.h>
CHANGE HISTORY
First released in Issue 1. Derived from Issue 1 of the SVID.
Issue 5
The vsnprintf () function is added.
Issue 6
The vfprintf (),
vprintf (), vsnprintf (), and
vsprintf () functions are updated for alignment with the
ISO/IEC 9899:1999 (“ISO C99”)
standard.
Issue 7
The vdprintf () function is added to complement the dprintf(3) function from The Open Group Technical Standard, 2006, Extended API Set Part 1.
POSIX.1-2008, Technical Corrigendum 1, XSH/TC1-2008/0703 [14] is applied.
Issue 8
Austin Group Defect 1496 is applied, adding the vasprintf () function.