NAME
vprintf(), vfprintf(), vsprintf(), vsnprintf() — print formatted output of a varargs argument list
SYNOPSIS
#include <stdarg.h>
#include <stdio.h>
int vprintf(const char *format, va_list ap);
int vfprintf(FILE *stream, const char *format, va_list ap);
int vsprintf(char *s, const char *format, va_list ap);
int vsnprintf(char *s, size_t maxsize, const char *format, va_list ap);
DESCRIPTION
vprintf(),
vfprintf(),
vsprintf(),
and
vsnprintf()
are the same as
printf(),
fprintf(),
sprintf(),
and
snprintf()
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>.
EXAMPLE
The following demonstrates how
vfprintf()
could be used to write an error routine:
#include <stdarg.h>
#include <stdio.h>
.
.
.
/*
* error should be called using the form:
* error(function_name, format, arg1, arg2...);
*/
/*VARARGS0*/
void
error(va_alist)
va_dcl
{
va_list args;
char *fmt;
va_start(args);
/* print out name of function causing error */
(void)fprintf(stderr, "ERROR in %s: ", va_arg(args, char *));
fmt = va_arg(args, char *);
/* print out remainder of message */
(void)vfprintf(stderr, fmt, args);
va_end(args);
(void)abort( );
}
APPLICATION USAGE
The interfaces
vprintf(),
vfprintf(),
vsnprintf()
and
vsprintf()
are thread-safe. These interfaces are not async-cancel-safe.
A cancellation point may occur when a thread is executing
vprintf()
or
vfprintf().
STANDARDS CONFORMANCE
vprintf(): AES, SVID2, SVID3, XPG2, XPG3, XPG4, FIPS 151-2, POSIX.1, ANSI C
vfprintf(): AES, SVID2, SVID3, XPG2, XPG3, XPG4, FIPS 151-2, POSIX.1, ANSI C
vsprintf(): AES, SVID2, SVID3, XPG2, XPG3, XPG4, FIPS 151-2, POSIX.1, ANSI C
