wrapper printf function that filters according to user preferences
If you want the PRIO_* definitions to be used as bit (using | and &), you must give each one of them its own bit:
unsigned short PRIO_HIGH = 0x0001;
unsigned short PRIO_NORMAL = 0x0002;
unsigned short PRIO_LOW = 0x0004;
The macro can be improved by using the do { } while (0) notation. It makes the calls to write_log act more like a statement.
#define write_log(priority,format,args...) do { \
if (priority & PRIO_LOG) { \
printf(format, ## args); \
} while(0)
You want to call vprintf() instead of printf() using the variable arguments "varargs" capabilities of C.
#include <stdarg.h>
int write_log(int priority, const char *format, ...)
{
va_list args;
va_start(args, format);
if(priority & PRIO_LOG)
vprintf(format, args);
va_end(args);
}
For more information, see something along the lines of this.
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.