Toby Toby - 1 year ago 130
C Question

Preprocessor concatenation for include path

I have a set of includes that reside in a far off directory meaning that including them requires a long include, such as:

#include "../../Path/to/my/file.h"

Where I have multiple of these it becomes a bit inconvenient so I am thinking I may be able to use a #define for the directory path and then concat the file name that I need, i.e.

#define DIR "../../Path/to/my/"
#define FILE1 "file.h"
#define FILE2 "anotherFile.h"

#include DIR FILE1 // should end up same as line in first example after pre-proc

However this does not work... is there anyway to concatenate within the workings of the C pre-processor suitable for this?

Answer Source

You can't customise the search path for include files like this, but you can tell the compiler where to look for include files. Many compilers -I option for that, e.g.:

gcc -c stuff.c -I/path/to/my/ -I/path/to/other/

If that makes your compilation command too long, you should write a Makefile or, if you are working in Visual Studio or similar IDE, customise the search path in your project settings.

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