Can you run a function on initialization in c?

Question

Is there an mechanism or trick to run a function when a program loads?

What I\'m trying to achieve...

void foo(void)
{
}

register_function(foo);
<         


        

Answer 1

Standard C does not support such an operation. If you don't wish to use compiler specific features to do this, then your next best bet might be to create a global static flag that is initialized to false. Then whenever someone invokes one of your operations that require the function pointer to be registered, you check that flag. If it is false you register the function then set the flag to true. Subsequent calls then won't have to perform the registration. This is similar to the lazy instantiation used in the OO Singleton design pattern.