Creating your own header file in C

终于跑起来了，含自定义 include .h 的c语言程序，超开心呀！

header files contain prototypes for functions you define in a .c or .cpp/.cxx file (depending if you're using c or c++).

You want to place #ifndef/#defines around your .h code so that if you include the same .h twice in different parts of your programs, the prototypes are only included once

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参考：http://stackoverflow.com/questions/7109964/creating-your-own-header-file-in-c

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foo.h #ifndef FOO_H_ /* Include guard */ #define FOO_H_ int foo(int x); /* An example function declaration */ #endif // FOO_H_ foo.c #include "foo.h" /* Include the header (not strictly necessary here) */ int foo(int x) /* Function definition */ { return x + 5; } main.c #include <stdio.h> #include "foo.h" /* Include the header here, to obtain the function declaration */ int main(void) { int y = foo(3); /* Use the function here */ printf("%d\n", y); return 0; } To compile using GCC gcc -o my_app main.c foo.c