Does Not enter main while debugging

Hi All,

I am using STM32 ARM cortex controller.I use UIlink debugger
I am new to controller programming. I have written a program which sets one of the GPIO Pin.
The program compiles with no errors. When I debug the code line by line, i could see that it doesnt enter my application, that is main program. It stops after SystemInit function. I cannot see it executing my functions.
Any idea on this would be appreciated.

Thanks in advance