C vprintf, vfprintf, vsprintf, and vsnprintf
Syntax
C vprintf, vfprintf, vsprintf, and vsnprintf have the following syntax.
int vprintf(char *format, va_list arg_ptr);int vfprintf(FILE *stream, const char *format, va_list arg_ptr);int vsprintf(char *buf, const char *format, va_list arg_ptr);int vsnprintf(char * restrict buf, size_t num, const char * restrict format, va_list arg_ptr);
Header
C vprintf, vfprintf, vsprintf, and vsnprintf
methods are from stdarg.h and stdio.h.
Description
The functions vprintf(), vfprintf(),
vsprintf(), and vsnprintf()
are functionally equivalent to
printf(), fprintf(),
sprintf(), and snprintf(), respectively
,except that the argument list has been replaced by a pointer to a list of arguments.
This pointer must be of type va_list, which is defined in the header stdarg.h.
Example
#include <stdio.h>
#include <stdarg.h>
//from ww w . ja va2 s.c om
void print_message(char *format, ...)
{
va_list ptr;
va_start(ptr, format);
vprintf(format, ptr);
va_end(ptr);
}
int main(void)
{
print_message("Cannot open file %s.", "test");
return 0;
}