On Tue, 2011-03-01 at 08:59 +0000, Jonathan Wakely wrote: > On 1 March 2011 05:11, <richardcavell@xxxxxxxx> wrote: > > Hi everyone. I've decided to learn C99, and so I'm passing -std=c99 to gcc. > > I've decided to write a Wikipedia bot in C (don't laugh). > > > > Owing partly to obsessive tendencies and partly due to the need for the bot > > to be robust in working unattended at high speed, I want to wrap printf in a > > wrapper that automatically detects when printf has failed and tells the > > user. The idea is that it is called like this: > > > > int res = safeprint ( __FILE__ , __LINE__ , "Blah" ) ; > > if ( res < 0 ) // uh oh > > > > But printf has variadic input. I am scratching my head wondering what is > > my best option: > > > > 1. Make safeprint a variadic function (I don't know how to do this) > > Use va_list, va_start, va_arg and va_end, defined by: > #include <stdarg.h> > > On GNU/Linux you should be able to say "man stdarg.h" to see usage examples. > > > 2. Turn on C++ and overload safeprint with different combinations of > > arguments > > A better option would be to use a C++ variadic template. > > > 3. Create multiple safeprint functions with different names, that take > > different combinations of arguments > > That would be inconvenient to use. I would have to agree with Jonathan here. In my experience with c++ (Qt) overloading has only caused me trouble. the va_list method is straight forward. Note that printf() even comes in a va_list compatible form. vprintf() Max S.
