Question

I just found out that the <stdlib.h> and <stdio.h> headers are located in the /usr/include folder in Ubuntu server, but I don’t find sys/types.h.

And I start to suspect the compiler won’t actually use the header file in the /usr/include folder.

Is this true, and where is the file located?

Answer 1

My Debian box (and hopefully Ubuntu haven’t butchered it too much in their zeal) has it in /usr/include/sys/types.h.

Your best bet is to execute:

find /usr/include -name types.h
find / -name types.h # if not found by one above

However, keep in mind that the development stuff may not even be installed on a server. Unless it’s a server for a compiler farm, it wouldn’t surprise me if the compiler and a bunch of other stuff was not part of the default install.

If the compiler is locating it somewhere and you just don’t know where, you can use something like:

echo "#include <sys/types.h>" | gcc -E -x c - | grep /types.h

to find out where it’s getting it from.

That gcc command line:

• stops after the pre-processing phase (-E);
• forces the file to be treated as C source code (-x c); and
• retrieves the program from standard input (-), in this case from the echo statement.

The final grep just strips out the unimportant lines leaving the ones that are likely to contain the location of the included file.