vsnprintf (3p) - Linux Manuals
vsnprintf: format output of a stdarg
PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.NAME
vfprintf, vprintf, vsnprintf, vsprintf - format output of a stdarg argument list
SYNOPSIS
#include <stdarg.h>
#include <stdio.h>
int vfprintf(FILE *restrict stream, const char *restrict
format,
int vprintf(const char *restrict format, va_list ap);
int vsnprintf(char *restrict s, size_t n,
const char *restrict format,
int vsprintf(char *restrict s, const char *restrict
format, va_list ap);
DESCRIPTION
The vprintf(), vfprintf(), vsnprintf(), and vsprintf() functions shall be equivalent to printf(), fprintf(), snprintf(), and sprintf() 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
ERRORS
Refer to fprintf().
The following sections are informative.
EXAMPLES
APPLICATION USAGE
Applications using these functions should call va_end(ap) afterwards to clean up.
RATIONALE
FUTURE DIRECTIONS
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .