Discrepancy between uname -r and /usr/include/linux/version.h

[lambert_anne]

Hi!

In the application I am developing I need to check the kernel version currently running to know which file I can include (specifically if POSIX message queues are implemented on the platform or if the program should use IPC).
Unfortunately there is a discrepancy between the /usr/include/linux/version.h and the real installed kernel.

> uname -r
2.6.9-42.ELsmp

> more /usr/include/linux/version.h
#define UTS_RELEASE "2.4.20"
#define LINUX_VERSION_CODE 132116
(...)

Which means that the application thinks kernel 2.4 is running whereas it is really 2.6.9.

What is the correct way to get the kernel version from a program? Or at least is there another way to know what is available on the running machine? I thought may be through the version of the glibc library but I need to determine this at compilation time and can't find a way to do this...

Anne

[the_unforgiven]

The files put under /usr/include are not kernel headers, but glibc headers (it has part of kernel headers for interfacing with kernel - albeit they're not the same as the headers used for kernel compilation).

The correct way to find out the running kernel version from C code is by using the uname() system call - use man 2 uname or uname manpage here.

HTH

[lambert_anne]

What I wanted to do is discover the running kernel version at compilation time and depending on the value include different parts of my code. For example in kernel2.6 POSIX message queues are implemented whereas if I have a 2.4 I must use IPC.
Is there a way to discover at compilation time what is available or not?

Anne

[likwid]

I'm sure this is possible with Makefiles but I have never set one up, sorry.