|
0
|
1
|
|
|
2 This directory is intended for project header files.
|
|
|
3
|
|
|
4 A header file is a file containing C declarations and macro definitions
|
|
|
5 to be shared between several project source files. You request the use of a
|
|
|
6 header file in your project source file (C, C++, etc) located in `src` folder
|
|
|
7 by including it, with the C preprocessing directive `#include'.
|
|
|
8
|
|
|
9 ```src/main.c
|
|
|
10
|
|
|
11 #include "header.h"
|
|
|
12
|
|
|
13 int main (void)
|
|
|
14 {
|
|
|
15 ...
|
|
|
16 }
|
|
|
17 ```
|
|
|
18
|
|
|
19 Including a header file produces the same results as copying the header file
|
|
|
20 into each source file that needs it. Such copying would be time-consuming
|
|
|
21 and error-prone. With a header file, the related declarations appear
|
|
|
22 in only one place. If they need to be changed, they can be changed in one
|
|
|
23 place, and programs that include the header file will automatically use the
|
|
|
24 new version when next recompiled. The header file eliminates the labor of
|
|
|
25 finding and changing all the copies as well as the risk that a failure to
|
|
|
26 find one copy will result in inconsistencies within a program.
|
|
|
27
|
|
|
28 In C, the usual convention is to give header files names that end with `.h'.
|
|
|
29 It is most portable to use only letters, digits, dashes, and underscores in
|
|
|
30 header file names, and at most one dot.
|
|
|
31
|
|
|
32 Read more about using header files in official GCC documentation:
|
|
|
33
|
|
|
34 * Include Syntax
|
|
|
35 * Include Operation
|
|
|
36 * Once-Only Headers
|
|
|
37 * Computed Includes
|
|
|
38
|
|
|
39 https://gcc.gnu.org/onlinedocs/cpp/Header-Files.html
|
