Re: fix if's that are followed by semicolons

[Andreas Mohr]

Hi,

On Tue, Sep 20, 2005 at 04:49:49PM +0900, Mike McCormack wrote:
> Found with:
>
> find . -name *.c -exec grep "if *([^)]*); *" {} ; -ls

Could you perhaps create a first version of a shell script tools/find_gotchas ?

We really need to make sure all those many things similar to this get fixed
on an ongoing basis.

Other gotchas could be

if (a = b)    (not easily identifiable since it might be legitimate, though)

HFILE x = 0;  (instead of INVALID_HANDLE or so)

Andreas Mohr

fix if's that are followed by semicolons

[Mike McCormack]

Andreas Mohr wrote:
> Could you perhaps create a first version of a shell script tools/find_gotchas ?

I have other things to do at the moment, so go ahead if you're feeling 
motivated.  I suspect you'll run into alot of false positives.  There 
might be a compiler switch to turn on warnings for these things too (ie. 
statements with no effect).

Mike

fix if's that are followed by semicolons

[Erik de Castro Lopo]

Mike McCormack wrote:
> Andreas Mohr wrote:
> > Could you perhaps create a first version of a shell script tools/find_gotchas ?
>
> I have other things to do at the moment, so go ahead if you're feeling 
> motivated.  I suspect you'll run into alot of false positives.  There 
> might be a compiler switch to turn on warnings for these things too (ie. 
> statements with no effect).

Gcc-4.0 catches this:

erikd@miles > cat test.c 
    int main (void)
    {
        if (0)  ;
        return 0 ;
    }
    erikd@miles > gcc-4.0 -W -Wall test.c -o /dev/null
    test.c: In function 'main':
    test.c:3: warning: empty body in an if-statement

Erik

fix if's that are followed by semicolons

[Mike McCormack]

Erik de Castro Lopo wrote:
> Gcc-4.0 catches this:
> erikd@miles > cat test.c 
> int main (void)
> {
>     if (0)  ;
>     return 0 ;
> }
> erikd@miles > gcc-4.0 -W -Wall test.c -o /dev/null
> test.c: In function 'main':
> test.c:3: warning: empty body in an if-statement

Yes, but only if you use -W -Wall, which wine unfortunately doesn't :/

bash-3.00$ cat > t.c
int boo(int arg) {
    if (arg);
    return 0;
}
bash-3.00$ /usr/local/gcc-4.0.1/bin/gcc -c -Wall t.c
bash-3.00$ /usr/local/gcc-4.0.1/bin/gcc -c -W -Wall t.c
t.c: In function 'boo':
t.c:2: warning: empty body in an if-statement

Mike

fix if's that are followed by semicolons

[Michael Stefaniuc]

Mike McCormack wrote:
> Erik de Castro Lopo wrote:
> > Gcc-4.0 catches this:
> > erikd@miles > cat test.c     int main (void)
> > {
> >     if (0)  ;
> >     return 0 ;
> > }
> > erikd@miles > gcc-4.0 -W -Wall test.c -o /dev/null
> > test.c: In function 'main':
> > test.c:3: warning: empty body in an if-statement
>
> Yes, but only if you use -W -Wall, which wine unfortunately doesn't :/

Properly documented (in the janitorial part on the wiki) this is good 
enough. No need to write an extra tool/script to catch those if 
problems. I once wrote a script for smatch to look for such cases but 
i'm not sure i finished it or at least it's not part of the standard 
smatch scripts I run.
> bash-3.00$ cat > t.c
> int boo(int arg) {
>    if (arg);
>    return 0;
> }
> bash-3.00$ /usr/local/gcc-4.0.1/bin/gcc -c -Wall t.c
> bash-3.00$ /usr/local/gcc-4.0.1/bin/gcc -c -W -Wall t.c
> t.c: In function 'boo':
> t.c:2: warning: empty body in an if-statement

bye
    michael