I'm trying to abstract out this logging API I'm using. The prototype for the logging function is
So I wanted to make my own functionCode:log(int level, char * fmt, ...)
That calls theirs. Is there some way I can pass the ... arg from my function into the actual logging function?Code:mylog(int level, char * fmt, ...)
You can't do that. At most, you can create a va_list out of the ellipsis and pass it to some function similar to `log' that takes a va_list in place of variable arguments. Or if your compiler supports variadic macros, then you can use one instead of a function call.
Stick close to your desks and never program a thing,
And you all may sit in the standards commitee!
All the standard variadic functions eg.
printf( const char *fmt, ... );
also have an equivalent varargs function
vprintf( const char *fmt, va_list ap );
Writing myprintf() would use the va_start/va_end macros, and call the vprintf() function at some point.
Unless you have a vlog(int level, va_list ap), you're pretty much stuck without resorting to extreme trickery.
If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
If at first you don't succeed, try writing your phone number on the exam paper.
Can't you use C99 variadic argument macro?
Code:#define mylog(a,...) do { mylogfunc(a,__VA_ARGS__); \ log(a,__VA_ARGS__); } while(0)
