gcc -I option flag

gcc -I adds include directory of header files.

Syntax

$ gcc -Idir [options] [source files] [object files] [-o output file]

Example

proj/src/myheader.h:

// myheader.h #define NUM1 5

myfile.c:

// myfile.c #include  #include "myheader.h"  
									 void main() {
									     int num = NUM1;     printf("num=%d\n", num); }

Build myfile.c without include directory proj/src :

$ gcc myfile.c -o myfile myfile.c:2:22: fatal error: myheader.h: No such file or directory compilation terminated. $

Build myfile.c with include directory proj/src :

$ gcc -Iproj/src myfile.c -o myfile $ ./myfile num=5
										 $