Re: gcc warnings

[Tom St Denis <tstdenis at ellipticsemi dot com>]

Humpolicek, Jiri - Acision wrote:
> Hi,
>             I have, from my point of view, strange problem. I want to tell gcc to report all compilation warnings, especially warnings about assigment from variable of greater type to variable with smaller type. For example, when I write following code and compile it with next command no warning is reported:
>
> c++ -o test test.cpp -Wall -Wextra -Wconversion -pedantic
>
> #include "stdio.h"
>
> int main()
> {
>         long a = 10000;
>         unsigned char b = a;
>
>         printf("%d\n", b);
>
>         return b;
> }
>
>   

The problem is that's not an error or problem as far as the C standard 
[and C++] goes.  So a warning for that while valid, would probably be 
out of line.

My recommendation is to simply not assign across types unless you have 
to.  If you have a function like

void myfunc(unsigned long somevalue)
{
}

Then never store somevalue in anything but an unsigned long unless 
you're sure of what you are doing.  Why would you write

char careless = somevalue;

just for the hell of it? 

Tom