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I recently upgraded from Kubuntu 12.04 to 13.04, a complete reinstall.

Using gcc 4.7.3. I compiled some programs to discover there is no /usr/include/sys directory. That is, types.h, stat.h, etc, are absent. They exist in the include/linux directory but not include/sys.

What's going on?

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  • What's the error message that GCC prints? Please edit the question to provide this and other information related to your problem.
    – edwin
    Feb 1, 2014 at 16:09
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    Do you have build essential installed?
    – Seth
    Feb 1, 2014 at 16:17
  • The couple of programs I have tried compile fine so there is no error message from gcc. I just can't figure where the header is coming from. I have an editor that builds references to functions and syscall and the like and it isn't happy that it can't find the directory.
    – Duck
    Feb 1, 2014 at 16:20
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    Yes, build-essential is up to date.
    – Duck
    Feb 1, 2014 at 16:22

5 Answers 5

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If you use Ubuntu on 64-bit (I can't text exactly right now on a 32-bit system), then the directory from the question is:

/usr/include/x86_64-linux-gnu/sys

Now, having this information, you can create symbolic links to those files if you really need them at that location (/usr/include/sys) using this on a terminal:

sudo ln -s /usr/include/x86_64-linux-gnu/sys/types.h /usr/include/sys/types.h
sudo ln -s /usr/include/x86_64-linux-gnu/sys/stat.h /usr/include/sys/stat.h

# ...etc
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  • Yes, 64 bit. I read something similar elsewhere and it seems like everything is in that directory but I am not certain how the headers are getting included from the "#include sys/stat.h" to the x86_64/sys directory. Is this some new fangled gcc injection feature? Off-hand I don't see any symlinks or the like that would (externally) lead to this behavior.
    – Duck
    Feb 1, 2014 at 16:37
  • Looks like we passed each other in the wind. So the bottom line is that the compiler is doing some magic but I may need to use some symlink hacks to make my editor happy?
    – Duck
    Feb 1, 2014 at 16:39
  • @Duck I just edited my answer before 2 min of your comments :)
    – Radu Rădeanu
    Feb 1, 2014 at 16:44
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install libc6-dev-amd64 if you working on a 64-bit linux. Type the following command on the ubuntu terminal:

sudo apt-get install libc6-dev-amd64
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Let's check what gcc's default include search path is. From this answer, we get this command:

gcc -xc -E -v -

At the end of the output, I see this on my machine:

ignoring nonexistent directory "/usr/local/include/x86_64-linux-gnu"
ignoring nonexistent directory "/usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../x86_64-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
 /usr/lib/gcc/x86_64-linux-gnu/4.8/include
 /usr/local/include
 /usr/lib/gcc/x86_64-linux-gnu/4.8/include-fixed
 /usr/include/x86_64-linux-gnu
 /usr/include

Notice the second-to-last line. That means that when you compile a C file with #include <sys/stat.h>, gcc will look for /usr/include/x86_64-linux-gnu/sys/stat.h before trying /usr/include/sys/stat.h, without us having to symlink anything.

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the sys directory is a unix/linux system header directory with a lots of system commands. Different brands/version linux may put it in different places. The following command can help you:

find /usr/include -type d -name sys
On my ubuntu 16 got the two
/usr/include/bsd/sys
/usr/include/x86_64-linux-gnu/sys

The first one is home to BSD unix system headers.
The second one is a directory containing Linux 64 bits system heads.

I run into problems with cmake not being able to find the sys/stat.h file. My temporary solution is to make a symbolic link

/user/local/include/sys/stat.h from /usr/include/x86_64-linux-gnu/sys/stat.h

I don't want to pollute the /usr/include directory, and I am only making a link to one particular header file and not the whole sys directory. I think this is a defect of cmake, so making minimal impact by making only one link. Hope this may help those who are suffering from the same problem.

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Since my architecture is amd64 there is no libc6-dev-amd64. The package to install is libc6-dev-i386.

That fixed the dependency for a CPAN-package.

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    'Since my architecture is amd64 there is no libc6-dev-amd64': what do you mean?
    – Marc Vanhoomissen
    Jan 22, 2018 at 11:50
  • What I mean is, that on x86_64 architecture, libraries/kernel/etc. packages have amd64 architecture. So, libc6-dev-amd64 is not available to install. Still the problem persists, some software expect to see /usr/include/sys/.
    – Jari Turkia
    Jan 22, 2018 at 12:11

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