what does it mean: warning: label `xxx' defined but not used

[Daniel]

Here is the code in question:

switch (msgtype)
{
MSG_S_LOGIN_FAIL :
// TODO
// display msg
//
break;
MSG_S_LOGGED_ON :
// TODO
// start
break;
MSG_S_REG_FAIL :
// TODO
// display msg
break;
MSG_S_REGISTERED :
// TODO
// start
//
break;
}

....and here are the warnings:

$ make
g++ -Wall -g -o0 client.cpp player.cpp -o tbclient.exe
client.cpp: In member function `void TClient::RecvMsg()':
client.cpp:69: warning: label `MSG_S_REGISTERED' defined but not used
client.cpp:65: warning: label `MSG_S_REG_FAIL' defined but not used
client.cpp:61: warning: label `MSG_S_LOGGED_ON' defined but not used
client.cpp:56: warning: label `MSG_S_LOGIN_FAIL' defined but not used

Here are the declarations:

const char MSG_S_LOGIN_FAIL = 'l';
const char MSG_S_LOGGED_ON = 'L';
const char MSG_S_REG_FAIL = 'r';
const char MSG_S_REGISTERED = 'R';

 

[Huibert Bol]

Here is the code in question:

switch (msgtype)
{
MSG_S_LOGIN_FAIL :

A clear case of a missing 'case'.

 

[Nick Keighley]

A clear case of a missing 'case'.

ie. try

switch (msgtype)
{
case MSG_S_LOGIN_FAIL:

you'll probably get a different set of errors

 

[Daniel]

The compiler doesn't realise that this is skeleton code. Since you don't do
anything, yet, in the switch, the labels are pointless and it is warning you
about that.

Thanks.

 

[Flash Gordon]

Here is the code in question:

switch (msgtype)
{
MSG_S_LOGIN_FAIL :
// TODO
// display msg
//
break;
MSG_S_LOGGED_ON :
// TODO
// start
break;
MSG_S_REG_FAIL :
// TODO
// display msg
break;
MSG_S_REGISTERED :
// TODO
// start
//
break;
}

....and here are the warnings:

It would be easier if you put your question in the body of the message,
not just in the subject line. You were asking about what these warnings
mean...

$ make
g++ -Wall -g -o0 client.cpp player.cpp -o tbclient.exe
client.cpp: In member function `void TClient::RecvMsg()':
client.cpp:69: warning: label `MSG_S_REGISTERED' defined but not used
client.cpp:65: warning: label `MSG_S_REG_FAIL' defined but not used
client.cpp:61: warning: label `MSG_S_LOGGED_ON' defined but not used
client.cpp:56: warning: label `MSG_S_LOGIN_FAIL' defined but not used

It's quite simple, it means that you have defined those labels but not
actually used them! You just think you've used them, but you are wrong!
For "switch labels", you need to use the "case" keyword, i.e.
case MSG_S_REGISTERED:
By not including the "case" keyword you have created "goto labels".

Here are the declarations:

const char MSG_S_LOGIN_FAIL = 'l';
const char MSG_S_LOGGED_ON = 'L';
const char MSG_S_REG_FAIL = 'r';
const char MSG_S_REGISTERED = 'R';

However, with those definitions I would not expect it to work in C!
Possibly C++, but that is a different language discussed in comp.lang.c++

In C I would expect you to use
#define MSG_S_LOGIN_FAIL 'l'
etc.
The reason being that in C using const does not give you a compile time
constant.

 

[Seebs]

MSG_S_LOGIN_FAIL :

This is a goto label, which you never goto.

Maybe you wanted a "case" statement, in which case, it'd be written:

case MSG_S_LOGIN_FAIL:

-s

 

[Seebs]

The compiler doesn't realise that this is skeleton code. Since you don't do
anything, yet, in the switch, the labels are pointless and it is warning you
about that.

Either you're joking or you missed the point badly. I can't tell which.

-s

 

[Flash Gordon]

Thanks.

I suggest you read the responses by everyone else, since Malcolm is
wrong about the cause of the problem.

 

[Richard Tobin]

switch (msgtype)
{
MSG_S_LOGIN_FAIL :
// TODO
// display msg
//
break;
MSG_S_LOGGED_ON :
// TODO
// start
break;
MSG_S_REG_FAIL :
// TODO
// display msg
break;
MSG_S_REGISTERED :
// TODO
// start
//
break;
}

client.cpp: In member function `void TClient::RecvMsg()':
client.cpp:69: warning: label `MSG_S_REGISTERED' defined but not used
client.cpp:65: warning: label `MSG_S_REG_FAIL' defined but not used
client.cpp:61: warning: label `MSG_S_LOGGED_ON' defined but not used
client.cpp:56: warning: label `MSG_S_LOGIN_FAIL' defined but not used

A helpful compiler would also give the warning "switch statement contains no
cases".

-- Richard

 

[Nick Keighley]

Pretty normal, given that your labels aren't doing anything (i.e. "not
used"), // TODO is not considered a statement, all the compiler sees is
break.

no. read the other posts