vfprintf -- Write Formatted Output to a File

SYNOPSIS
#include <stdarg.h>
#include <stdio.h>
int vfprintf(FILE *f, const char *format, va_list arg);
DESCRIPTION
vfprintf
is equivalent to fprintf
with arg
replacing the variable-argument list.
arg
has been initialized by the va_start
macro and possibly va_arg
calls. vfprintf
does not invoke the
va_end
macro. See va_arg
, va_end
, and va_start
for
details on varying-length argument-list functions.
RETURN VALUE
vfprintf
returns the number of characters transmitted to the output
stream or a negative value if an output error occurs.
EXAMPLE
This example sends an error message prefix with
fprintf
and sends the remaining text with vfprintf
:
#include <stdarg.h>
#include <stdio.h>
void error(char *fname, char *format, ...)
{
va_list args;
va_start(args, format);
fprintf(stderr, "ERROR in %s: ", fname);
vfprintf(stderr, format, args);
va_end(args);
}
RELATED FUNCTIONS
fprintf
, va_start
, vprintf
SEE ALSO