Re: Wishlish: GCC option for explicit booleans

[Peter Lupton NCH Swift Sound <pl at nch dot com dot au>]

Maybe I gave a too simple example on my first post. Another example common 
error which would be prevented by blocking implicit bool conversion might be:

   if (strcmp(szMyName, "Peter"))  printf("Hello Peter");

This bad error currently just slips through. If we gave an option to only 
accept explicit bools then the error would be caught (because strcmp 
returns int not bool).


At 10:27 AM 3/10/2005, Nicholas Nethercote wrote:
> > C++ would be a better language if the boolean type did not implicitly
> > convert from int. For example, many novice programmers make the
> > mistake.
> >
> >   if (i = j) dosomething(); // Should be i == j
> >
> > If conversion to boolean required explicit this would all be solved. It
> > would mean all the old code with expressions like "while (p) ... "
> > would need to be changed to "while (p != NULL) ...". But I think the
> > change would be well justified.
> >
> > What about a GCC option to turn off implicit conversion to boolean?
>
> [~] more a.cpp
> int main(void)
> {
>     int i = 0, j = 0;
>     if (i = j)
>         return 0;
>     else
>         return 1;
> }
> [~] g++ -Wall a.cpp
> a.cpp: In function `int main()':
> a.cpp:4: warning: suggest parentheses around assignment used as truth value
>
> Nick


Peter Lupton
pl@nch.com.au

NCH Swift Sound
Unit 13, Level 3
28 University Avenue
GPO Box 1169
Canberra ACT 2601
Australia
www.nch.com.au