On 2009-07-16 05:07:23 (-0400), Robert P. J. Day <rpjday@xxxxxxxxxxxxxx> wrote: > > i can see that, after i run "make modules_prepare", i have a new > directory in the kernel source tree "include/config" full of empty > header files. what is the function of this directory? is it just > keeping track of which header files have been processed for exporting > to userspace or what? That directory is not used for header files at all. It's part of a clever trick to optimize the kernel build. The kernel configuration (stored in .config) is used to generate a header file which is used throughout the kernel. The problem is that changing one option means all files which include config.h will need to be rebuilt, even though most of them may not be affected by that option. This is solved by removing the makefile dependency on config.h and replacing it by a dependency on one of the files in include/config. Each file there corresponds to a configuration option. Whenever that option is changed the configuration system touches that file (updating its timestamp causing make to rebuild all dependant files. Regards, Kristof -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
