Updated: April 19, 2023 |
Write formatted output to standard output (varargs)
#include <stdio.h> #include <stdarg.h> int vprintf( const char* format, va_list arg );
libc
Use the -l c option to qcc to link against this library. This library is usually included automatically.
The vprintf() function writes output to the file stdout, under control of the argument format.
The vprintf() function is a varargs version of printf().
The number of characters written, or a negative value if an output error occurred (errno is set).
Use vprintf() in a general error message routine:
#include <stdio.h> #include <stdlib.h> #include <stdarg.h> void errmsg( const char* format, ... ) { va_list arglist; printf( "Error: " ); va_start( arglist, format ); vprintf( format, arglist ); va_end( arglist ); } int main( void ) { errmsg( "%s %d %s", "Failed", 100, "times" ); return EXIT_SUCCESS; }
Safety: | |
---|---|
Cancellation point | Yes |
Interrupt handler | No |
Signal handler | No |
Thread | Yes |