dprintf()

Write output to a file associated with a file descriptor

Synopsis:

#include <stdio.h>

int dprintf( int filedes, 
             const char* format, 
             ... );

filedes: A file descriptor that's associated with the file where you want to send the output.
format: A string that specifies the format of the output. The formatting string determines what additional arguments you need to provide. For more information, see printf().

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

The dprintf() function writes output to the file associated with the file descriptor filedes, under control of the format specifier.

The number of characters written, or a negative value if an output error occurred (errno is set).