Re: Unable to cross build for Windows

[Torbjorn SVENSSON]

On 2023-06-09 09:11, Eli Zaretskii wrote:
> > From: Martin Dorey <Martin.Dorey@hitachivantara.com>
> > CC: "bug-make@gnu.org" <bug-make@gnu.org>
> > Date: Fri, 9 Jun 2023 06:32:28 +0000
> > msip_labels:
> >
> > #include <stdint.h>
> >
> > intptr_t _get_osfhandle(int);
> > typedef void* HANDLE;
> >
> > HANDLE fn() {
> >    return (HANDLE)_get_osfhandle(0);
> > }
> > martind@sirius:~/tmp/svensson-2023-06-08$ gcc -c -Wbad-function-cast make.c
> > make.c: In function ‘fn’:
> > make.c:7:10: warning: cast from function call of type ‘intptr_t {aka long int}’ 
> > to non-matching type ‘void *’ [-Wbad-function-cast]
> >     return (HANDLE)_get_osfhandle(0);
> >            ^
> > martind@sirius:~/tmp/svensson-2023-06-08$
> >
> > That's gcc-6.3, but it's much the same in every version I tested from gcc-4.4 
> > to gcc-10.  A random version's man page, 
> > https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Warning-Options.html, explains the 
> > flag as to:
> >
> > > Warn when a function call is cast to a non-matching type. For example, warn if 
> > > a call to a function returning an integer type is cast to a pointer type.
> >
> > I fear they mean exactly what they say there.  So, while you might call it a 
> > mistake, I don't think it's an accident.  
> > https://stackoverflow.com/a/35308713/18096 has some explanation of why it might 
> > sometimes be useful... and how it could be sidestepped by a change to Gnu Make, 
> > like our new friend wished for.
>
> Yes, it sounds like -Wbad-function-cast will always emit a warning in
> such cases, and one cannot use it with the likes of _get_osfhandle,
> which _require_ such casts.
>
> You can, of course, work around it; the following compiles without a
> warning:
>
> #include <stdint.h>
>
> intptr_t _get_osfhandle(int);
> typedef void* HANDLE;
>
> HANDLE fn() {
>    intptr_t handle = _get_osfhandle(0);
>    return (HANDLE)handle;
> }

Okay, lets go this way to fix the warning to allow building with 
-Wbad-function-cast.

The only thing left, that I don't know how to handle, is the use of O() where 
the 3rd parameter is not a string literal.

src/job.c: In function 'create_batch_file':
src/job.c:365:3: error: format not a string literal and no format arguments 
[-Werror=format-security]
   O (fatal, NILF, error_string);
   ^

is it okay to change this to: fatal (NILF, 0, error_string);
or is there a better way to get around this warning?