Use gcc preprocessor to define filename for #include

Question

I would like to specify the name of a C include file at compile time as a C flag.

e.g.

#include MY_INCLUDE_FILE
int main(int argc, const char * argv[]) {...}

Would be expaned by the pre-processor to

#include "some_incfile.h"
int main(int argc, const char * argv[]) {...}

Doing something like this

gcc -DMY_INCLUDE_FILE="some_incfile.h" main.c

I have attempted using the stringizing operator # to expand but have only gotten errors such as error: expected "FILENAME" or <FILENAME>

Is this even possible? -D define is not entirely necessary, the important part is that the include filename can be set from the gcc command line

Answer 1

You have to escape the ":

gcc -DMY_INCLUDE_FILE=\"some_incfile.h\" main.c