Hi, Is there any way to specify in the code the optimization value like (-O2 or -O3) instead of on the command line. I want #include <stdio.h> ... ... return 0 } to be compiled with -O2 or -O3 or some better optimization than standard gcc flags like gcc a.c .I have only 1 file. The problem is i can't modify the makefile. The constraint is it get it optimized from the code using some technique like macro for (preprocessor ) or something. Can anyone help me on this. Regards Nik