Hi All I installed gcc 4.2.3 with gfortran on AIX 5.3. Compiled and created a shared object with programs written in C. Compiled fortran code with gfortran and tried to link with the earlier created shared object. I get the following error undefined reference to `.rtregister_' where rt_register is the 'C' function call that is required. The same set of programs worked fine on a Linux box with g77. Am I missing anything? Your help will be greatly appreciated. With Regards Vardhan