Question

I am enhancing a tool.
Please note that this tool will be linked to test program, which will have main( ) function, so my tool can’t have main. What this tool has is a number of functions which the test program will use.

Now additionally, i want to add a timer to this tool. The idea is: when the test program is linked to this tool and starts, the timer should automatically start.

If this was C++, i would have created a class with a constructor, so that whenever the class is loaded, the constructor is called first, and i can initialize my timer inside the constructor.

If this was Java, i would have simply created a global static block, and put the timer code inside the static block.

But my tool is purely in C in Linux, so how can i achieve this goal?

Please help me.

Answer 1

This looks like your case also:

How do I get the GCC __attribute__ ((constructor)) to work under OSX?

From GCC docs:

constructor
destructor
constructor (priority)
destructor (priority)

The constructor attribute causes the
function to be called automatically
before execution enters main ().
Similarly, the destructor attribute
causes the function to be called
automatically after main () has
completed or exit () has been called.
Functions with these attributes are
useful for initializing data that will
be used implicitly during the
execution of the program.