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

Kevin Buettner
2002-02-08T23:55:42Z

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