Date: Thu, 13 Mar 1997 13:09:46 +0200 (IST)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
To: Beautiful Savior Lutheran Church <av568 AT rgfn DOT epcc DOT edu>
cc: djgpp AT delorie DOT com
Subject: Re: DJGPP inconsistencies?
In-Reply-To: <5g7vah$be8@news.epcc.edu>
Message-ID: <Pine.SUN.3.91.970313130930.6426F-100000@is>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII


On 13 Mar 1997, Beautiful Savior Lutheran Church wrote:

>         I have noticed a few inconsistencies with the DJGPP compiler over 
> other C compilers I use.
>         The first one is that the lines:
> 
>         for(int i=0; i<256; i++)
>         {       someFunction(i);
>         }
> 
>         won't compile SOMETIMES (?!?!?!), yet the lines:
> 
>         int i;
>         for (i=0; i<256; i++)
>         {       someFunction(i);
>         }
> 
>         works everytime...why?

Please always post the relevant details.  In this case, you should
have explained what does ``won't compile'' mean.  Did you get an error
message?  If so, please post this message and the command line you
used to compile your code.  It is very hard to guess what your
problems are without that info.

One possible reason might be that you put the first fragment on a file
with .c extension.  GCC treats such files as C programs, and you can't
declare a variable inside a for loop in C.  If that's a C++ program,
call the file .cc or .cpp, and it will compile.

Another possibility is that you use `i' outside the for loop, in which
case GCC will say that a variable declared inside the for loop is not
valid outside it, according the latest C++ draft standard.

> 
>         Also, I sometimes get random compiler "parse" errors when I include 
> the following code in a program:
> 
>         char *str;
>         if ( (str = getenv("DEM_PATH")) == NULL) {
>                 printf("\"DEM_PATH\" environment variable not set\n");
>                 exit(1);
>         }
> 
>         Yet again...WHY?

It depends on the surrounding context, I guess, because the fragment
seems OK to me by itself.  Again, please post the shortest complete
function source that, when compiled, exhibits the problem, and also
post the exact error message(s) printed by GCC.