Re: I would like to help implement stdint.h

["Joseph S. Myers" <jsm at polyomino dot org dot uk>]

On Fri, 10 Oct 2003, Jason Catena wrote:

> Since stdint.h is platform-dependent, I was thinking of writing a
> small program that would translate a description of the type sizes on
> the target to a finished stdint.h file. Alternately, I could create a
> library of stdint.h files, but it seems more efficient and flexible to
> create it in the fly.

The current thinking is that you should follow the same approach now used
for <limits.h> and <float.h> - that is, have a single stdint.h file that
uses macros predefined by the compiler to determine the types involved.  
Because many targets can have their type sizes changed at compiler runtime
with -m options, generating a <stdint.h> file at compiler build time isn't
a feasible approach.

There will need to be sensible defaults for the types, as well as target
macros to override them.  A fair amount of work will be involved in going
through supported targets which have their own <stdint.h>, such as all
glibc-based targets, to ensure that GCC's types agree with those systems'
types.  This is also necessary on systems which have <inttypes.h> but not
<stdint.h> (such as Solaris).  Note that GCC will also need to gain an
awareness of sig_atomic_t, which it previously hasn't needed to know about
(and some embedded targets may not have at all; see DR#248).

<stdint.h> may also need to be compatible with what various systems' other
headers expect of it or of <inttypes.h> (try to make something more
comprehensible than GCC's <stddef.h>).

Some fixincludes work may also be needed to make existing system headers
work well with GCC's <stdint.h>, especially on systems which have
<inttypes.h> only.

-- 
Joseph S. Myers
jsm@polyomino.org.uk