wrapper printf function that filters according to user preferences

Question

My program writes to a log and to stdout. Every message, however, has a certain priority and the user specifies in Preferences which priorities go to which stream (log or stdout

Answer 1

I think Jeff's idea is the way to go, but you can also accomplish this with a macro without using vprintf. This might require gcc:

#define write_log(priority,format,args...)        \
                  if (priority & PRIO_LOG) {      \ 
                      printf(format, ## args);    \
                  }

Check here for info about how this works.