[splint-discuss] [splint-discuss glib header and empty #define's

[Richard A. O'Keefe]

> At least using the gcc compiler, the difference between a blank  
> string and a
> semicolon in that context seems insignificant (they both compile,  
> and they
> both do nothing. I'm not sure if there are any technicalities  
> involved,
> however.)

(a) What you are talking about is NOT a blank string " " or an empty  
string ""
     but an empty right hand side or empty expansion.
(b) Accepting ";" as a declaration is a gcc extension.  According to  
both the
     old (C89) and the new (C99) C standards, it is an outright  
syntax error.
     No ifs, buts, maybes, or technicalities:  it's just not part of  
the language.
(c) Most annoyingly, 'gcc -ansi' does not report this mistake in the  
header.
     What is the point of a command line switch to enforce a standard  
if it
     doesn't enforce the standard?  You have to use 'gcc -ansi - 
pedantic' to get
	warning: ISO C does not allow extra ';' outside of a function
     but at least gcc *will* tell you this if you beg hard enough.

It looks as though the header in question was written by someone  
pretty clueless.

>
>> (I have no idea why the author of that header has them expand to
>> semicolons; I can't offhand think of any situation where a linkage
>> declaration would be appropriate in C++ and a semicolon would be  
>> needed
>> in C. But a lot of GNU code is rather poor C.)

I can't think of any place where a linkage declaration would be  
appropriate
in C++ and a bare semicolon would even be *legal* in standard C.
>

> I went to re-produce this error, with a file "test.c" containing
> #include <glib/glib.h>
> int main  {return 0;}
> (which is all I needed to cause the error before).
> Which I proceeded to (attempt to) compile using the command
> gcc -l glib-2.0 test.c 2>&1|less

I wonder how experienced you are with gcc?
To get gcc to do anything resembling decent error reporting you need
at a *minimum*
	gcc -ansi -pedantic -O2 -Wall
There are plenty of other -W options you may wish to enable that are not
included in -Wall.  Some of the defects -Wall detects are only enabled
if you have at least -O2.