c - Is there a macro definition to check the Linux kernel version?

Question

I'm wondering if there is a gcc macro that will tell me the Linux kernel version so I can set variable types appropriately. If not, how would I go about defining my own macro that does this?

Answer 1

The linux/version.h file has a macro called KERNEL_VERSION which will let you check the version you want against the current linux headers version (LINUX_VERSION_CODE) installed. For example to check if the current Linux headers are for kernel v2.6.16 or earlier:

#include <linux/version.h>

#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,16)
...
#else
...
#endif

A better way to get the version information at run-time is to use the utsname function in include/linux/utsname.h.

char *my_kernel_version = utsname()->release;

This is essentially how /proc/version gets the current kernel verison.

See also

Getting kernel version from linux kernel module at runtime