问题
When I write C programs in Linux, and then compile them using gcc, I am always curious about where those header files are. For example, where stdio.h is. More generally, where is stdbool.h?
What I want to know is not only where it is, but also how to get those places, for example, using shell command or using the C programming language.
回答1:
gcc -H ... will print the full path of every include file as a side-effect of regular compilation. Use -fsyntax-only in addition to get it not to create any output (it will still tell you if your program has errors). Example (Linux, gcc-4.7):
$ cat > test.c
#include <stdbool.h>
#include <stdio.h>
^D
$ gcc -H -fsyntax-only test.c
. /usr/lib/gcc/x86_64-linux-gnu/4.7/include/stdbool.h
. /usr/include/stdio.h
.. /usr/include/features.h
... /usr/include/x86_64-linux-gnu/bits/predefs.h
... /usr/include/x86_64-linux-gnu/sys/cdefs.h
.... /usr/include/x86_64-linux-gnu/bits/wordsize.h
... /usr/include/x86_64-linux-gnu/gnu/stubs.h
.... /usr/include/x86_64-linux-gnu/bits/wordsize.h
.... /usr/include/x86_64-linux-gnu/gnu/stubs-64.h
.. /usr/lib/gcc/x86_64-linux-gnu/4.7/include/stddef.h
.. /usr/include/x86_64-linux-gnu/bits/types.h
... /usr/include/x86_64-linux-gnu/bits/wordsize.h
... /usr/include/x86_64-linux-gnu/bits/typesizes.h
.. /usr/include/libio.h
... /usr/include/_G_config.h
.... /usr/lib/gcc/x86_64-linux-gnu/4.7/include/stddef.h
.... /usr/include/wchar.h
... /usr/lib/gcc/x86_64-linux-gnu/4.7/include/stdarg.h
.. /usr/include/x86_64-linux-gnu/bits/stdio_lim.h
.. /usr/include/x86_64-linux-gnu/bits/sys_errlist.h
The dots at the beginning of each line count how deeply nested the #include is.
回答2:
If you use gcc, you can check a specific file with something like:
echo '#include <stdbool.h>' | cpp -H -o /dev/null 2>&1 | head -n1
-H asks the preprocessor to print all included files recursively. head -n1 takes just the first line of output from that, to ignore any files included by the named header (though stdbool.h in particular probably doesn't).
On my computer, for example, the above outputs:
. /usr/lib/gcc/x86_64-linux-gnu/4.6/include/stdbool.h
回答3:
locate stdio.h
or
mlocate stdio.h
but locate relies on a database, if you have never updated it
sudo updatedb
you can also enquire gcc to know what are the default directories that are scanned by gcc itself:
gcc -print-search-dirs
回答4:
During the preprocessing all preprocessor directives will be replaced with the actuals. Like macro expansion, code comment removal, including the header file source code etc...
we can check it by using the 'CPP' - C PreProcessor command.
For example in the command line,
cpp Filename.c
It will display the preprocessed output.
回答5:
One approach, if you know the name of the include file, would be to use find:
cd /
find . -name "stdio.h"
find . -name "std*.h"
That'll take a while as it goes through every directory.
回答6:
Use gcc -v and you can check the include path.
Usually, the include files are in /usr/include or /usr/local/include depending on the library installation.
回答7:
Most standard headers are stored in /usr/include. It looks like stdbool.h is stored somewhere else, and depends on which compiler you are using. For example, g++ stores it in /usr/include/c++/4.7.2/tr1/stdbool.h whereas clang stores it at /usr/lib/clang/3.1/include/stdbool.h.
回答8:
I think the generic path is:
/usr/lib/gcc/$(ls /usr/lib/gcc/)/$(gcc -v 2>&1 | tail -1 | awk '{print $3}')/include/stdbool.h
回答9:
When I was looking for (on Fedora 25) I used "whereis stdio.h" For me, It was in /usr/include/stdio.h, /usr/shar/man/man3/stdio,3.gx. But when you are looking for the file, use whereis or locate
回答10:
Use vim to open your source file and put the curses on stdio.h and in normal mode, command 'gf' will let vim open the stdio.h file for you.
'Ctr + g' will let vim display the absolute path of stdio.h
来源：https://stackoverflow.com/questions/13079650/how-can-i-find-the-header-files-of-the-c-programming-language-in-linux