Hi Marvin, there exists a macro in the kernel: KERNEL_VERSION(a,b,c) which converts a kernel version triplet to an internal used variable named LINUX_VERSION_CODE. So to check for 2.6.24, do: #if (KERNEL_VERSION(2.6.24) > LINUX_VERSION_CODE) <use IRQF_SHARED> #else <use SA_SHIRQ> #endif Hoe this helps, Joern