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gccmakefileheader-files

How to include headers from another directory (but not knowing which)

I am trying to compile module. I can do so by calling make, which calls

make -C /lib/modules/$(shell uname -r)/build/ M=$(PWD) modules

But I want to see preprocessed output, So I am trying to compile manually with cc -E file.c. The problem is, It cannot see header <linux/init.h>:

fatal error: linux/init.h: No such file or directory
 #include <linux/init.h>

I have notice, when make is called, it first enter this dir /usr/src/linux-headers-5.0.0-38-generic, There is probably the header, but I do not know where. I have tried gcc -E -I'/usr/src/linux-headers-5.0.0-38-generic file.c, but still the same error. So how is possible to include kernel headers (which <linux/init.h> is) in user mode - that is how to include headers from another dir?

PS: as @uzsolt in comments suggested, I add include to the end of path: gcc -I /usr/src/linux-headers-5.0.0-38-generic/include. But then another header is missing - <asm/linkage.h>, and again - I have no clue in what dir this header is.

Solution

  • You should use find command: find /usr/src/linux-headers-5.0.0-38-generic -name MISSED_FILE.

    I don't know your linux distribution but I think you should add these parameters to gcc:

    -I/usr/src/linux-headers-5.0.0-38-generic/include -I/usr/src/linux-aws-headers-5.3.0-1003/arch/x86/include/