gcc使用笔记

1.如何在gcc中传输宏定义？

参考如下红色部分，可以传入宏定义

gcc [-c|-S|-E] [-std=standard]
[-g] [-pg] [-Olevel]
[-Wwarn...] [-pedantic]
[-Idir...] [-Ldir...]
[-Dmacro[=defn]...] [-Umacro]
[-foption...] [-mmachine-option...]
[-o outfile] [@file] infile...

示例：

#include <stdio.h>

int main(void)
{
#ifdef TEST
    printf("gcc has predefine!\n");
#else
    printf("gcc no predefine\n");
#endif
    return ;
}

[root@localhost c]# gcc gcc_D_test.c -DTEST
[root@localhost c]# ./a.out
gcc has predefine!

[root@localhost c]# gcc gcc_D_test.c
[root@localhost c]# ./a.out
gcc no predefine