C中的字符串比较（strcmp）问题

Question

I'm newbie in C. I want to compare string that I use '#DEFINE' and char buf[256]. This is my code.

#define SRV_SHOWMENU "SRV_SHOWMENU"
#define SRV_LOGIN_TRUE = "SRV_LOGIN_SUC"
#define SRV_LOGIN_FAIL = "SRV_LOGIN_FAIL"
#define SRV_REGISTER_OK = "SRV_REGISTER_SUC"
#define SRV_REGISTER_FAIL = "SRV_REGISTER_FAIL"
char buf[256];      // buffer for client data
...
...
...
...
...
...
if(strcmp(buf,SRV_SHOWMENU) == 0 || strcmp(buf,SRV_REGISTER_FAIL) == 0)
{

}

My C compiler tell me the systax error that "../src/server.c:417: error: expected expression before '=' token". But if I change to "if(strcmp(buf,SRV_SHOWMENU) == 0)" just one compare is ok.

Thank you.

Answer 1

You don't need to use '=' sign after #define. You can read more here .

Answer 2

As already said, remove the = signs in the #defines

#define SRV_SHOWMENU "SRV_SHOWMENU" 
#define SRV_LOGIN_TRUE "SRV_LOGIN_SUC" 
#define SRV_LOGIN_FAIL "SRV_LOGIN_FAIL" 
#define SRV_REGISTER_OK "SRV_REGISTER_SUC" 
#define SRV_REGISTER_FAIL "SRV_REGISTER_FAIL" 
char buf[256];      // buffer for client data 
... 
if(strcmp(buf,SRV_SHOWMENU) == 0 || strcmp(buf,SRV_REGISTER_FAIL) == 0) 
{ 

}

With the = in, the pre compiler will turn if(strcmp(buf,SRV_SHOWMENU) == 0 || strcmp(buf,SRV_REGISTER_FAIL) == 0) into

if(strcmp(buf,"SRV_SHOWMENU") == 0 || strcmp(buf,= "SRV_REGISTER_FAIL") == 0)