Re: use of program_name

[Paul Eggert]

Dave Love <address@hidden> writes:

> Paul Eggert <address@hidden> writes:
>
>> Under the current approach, it's the caller's responsibility to arrange
>> for a program_name variable that works, either by using the progname
>> module, or by rolling their own program_name variable.
>
> So gnulib shouldn't be used for libraries (or at least not unless you
> avoid modules calling `error' or accept errors spewing junk messages)?

It is a problem, yes.  However, it's not quite as bad as that.
The library can arrange for program_name to be initialized
before it is used.

>> I suppose it might make sense for error.c to avoid using program_name
>> if it's null.
>
> That's probably a good idea, but why can't it be initialized to null
> in error.c?

Because the current convention is to put this declaration in the main
program, at the top level:

char *program_name;

Hence the main program has allocated program_name, and has arranged
for it to be initialized to null.  If we put a similar declaration in
error.c, it would cause two different definitions of program_name, and
some non-Unix linkers reject this.  (The C Standard allows them to
reject it.)

> (If the interface to it was just set_program_name, it could be private.)

Yes, that would be a better convention.  This will require revamping
pretty much everybody that uses program_name, but I think it's worth
the pain.  What do others think?