Re: Remove true/false from GDB ....

[Kevin Buettner <kevinb@redhat.com>]

On Feb 8,  6:31pm, Andrew Cagney wrote:

> This is fallout from the recent <stdbool.h> problem.
> 
> "bfd.h" was providing ``true'' and ``false'' as convenience 
> enums/macros/...  They unfortunatly clash with systems that provide 
> <stdbool.h> (a header in c99?) and even some systems that don't.  The 
> relevant code block is:
> 
> /* I'm sure this is going to break something and someone is going to
>     force me to change it.  */
> /* typedef enum boolean {false, true} boolean; */
> /* Yup, SVR4 has a "typedef enum boolean" in <sys/types.h>  -fnf */
> /* It gets worse if the host also defines a true/false enum... -sts */
> /* And even worse if your compiler has built-in boolean types... -law */
> /* And even worse if your compiler provides a stdbool.h that conflicts
>     with these definitions... gcc 2.95 and later do.  If so, it must
>     be included first.  -drow */
> #if ...
>    ... many valiant attemts to define true and false ...
> #else
> /* Use enum names that will appear nowhere else.  */
> typedef enum bfd_boolean {bfd_fffalse, bfd_tttrue} boolean;
> #endif
> 
> In short, bfd.h should never have been polluting the name space with 
> ``true'' and ``false''.
> 
> So the proposal is for "bfd.h" to remove all the above code and instead 
> just define:
> 
>    typedef int bfd_boolean;
> 
> i.e. 0 is false, non-zero is true, just like C intended :-)
> 
> Problem is, some blocks of GDB make use of ``true'' and ``false'' and 
> they will need to be changed.  Two possabilities come to mind:
> 
> 	#include "gdb_stdbool.h"
> 		which would wrap <stdbool.h>
> 
> 	zap ``true'' and ``false''
> 
> I've strong preferences for the latter.  I think BFD serves as a very 
> compelling example of what not to do :-)
> 
> thoughts?

If GDB made widespread use of ``true'' and ``false'', I'd suggest
converting these occurences to ``gdb_true'' and ``gdb_false''.  I've
just looked though and GDB has surprisingly few uses of ``true'' and
``false''.  That being the case, I like Andrew's latter suggestion of
just zapping them.

Here's the results of my search after removing the occurrences of
lines containing true and false in comments:

./memattr.c[34]:   false,			/* hwbreak */
./memattr.c[35]:   false,			/* cache */
./memattr.c[36]:   false				/* verify */
./memattr.c[185]: 	attrib.hwbreak = true;
./memattr.c[187]: 	attrib.hwbreak = false;
./memattr.c[191]: 	attrib.cache = true;
./memattr.c[193]: 	attrib.cache = false;
./memattr.c[197]: 	attrib.verify = true;
./memattr.c[199]: 	attrib.verify = false;
./corelow.c[172]: 	  return (true);
./corelow.c[175]:   return (false);
./irix5-nat.c[437]:   abfd->cacheable = true;
./osfsolib.c[256]:   abfd->cacheable = true;
./solib.c[240]:   abfd->cacheable = true;
./symfile.c[1097]:   sym_bfd->cacheable = true;

Kevin