Kin Cho (kin@isi.com) wrote:
: CC j.C
: "j.C", line 2: error: label gotolab  undefined
: Compilation failed

goto?  They should have killed that thing in C++. #B^)

--

     cout << "cman@netcom.com\n";

In article <29krheINNag6@chief.isi.com>, kin@isi.com (Kin Cho) writes:
|> This program compiles and runs fine as a C program but my Sun C++
|> compiler won't compile it as a C++ program:
|>
|> #include <stdio.h>
|> main()
|> {
|>    if (1)
|>       goto gotolab;
|>    if (2)
|>       printf("2\n");
|>    else
|> gotolab:
|>       printf("!2\n");
|> }
|>
|> CC j.C
|> "j.C", line 2: error: label gotolab  undefined
|> Compilation failed
|>
|> Is this a cfront bug or an undocumented difference between C and C++?

I experimented a little bit more on different stations and different systems :
here are the results :

DECstation Ultrix:  cc (c compiler)    : compilation passed
      cxx (c++ compiler) : compilation passed

      gcc (c compiler)   : compilation passed
      g++ (c++ compiler) : I don't have it installed

DEC ALPHA OSF/1  :  cc                 : passed
      cxx                : passed
                    gcc                : passed
                    g++                : passed

SUN              :  cc                 : passed
                    CC                 : failed (as you mentioned)
      gcc                : passed
                    g++                : passed

VAX/VMS 5.5      :  cc (vax C compiler): failed (gotolab : undefined)
                    gcc                : failed (gotolab : undefined)
                    I dont have any C++ compiler on VAX/VMS


On my surprise, C compilers on VMS both find an error although
C compilers do not complain on UNIX systems.

Well...

Daniel Lenzi

So, no general rules can be found...

In article <cmanCExGpt.G24@netcom.com> Mike Austin, cman@netcom.com
writes:
>Kin Cho (kin@isi.com) wrote:
>: CC j.C
>: "j.C", line 2: error: label gotolab  undefined
>: Compilation failed
>
>goto?  They should have killed that thing in C++. #B^)
>


Yeah, that's a great idea, let's start another goto war...

rEnE

kin@isi.com (Kin Cho) writes:

>This program compiles and runs fine as a C program but my Sun C++
>compiler won't compile it as a C++ program:
>
>#include <stdio.h>
>main()
>{
>   if (1)
>      goto gotolab;
>   if (2)
>      printf("2\n");
>   else
>gotolab:
>      printf("!2\n");
>}
>"j.C", line 2: error: label gotolab  undefined
>
>Is this a cfront bug or an undocumented difference between C and C++?

I suspect the former.  Cfront is a bit premature at optimizing out
unreachable code before doing any semantic analysis on it - I suspect
that in this case it is "optimizing" out the else clause (including
the label) because it thinks it is unreachable.

--
Fergus Henderson                     fjh@munta.cs.mu.OZ.AU

This program compiles and runs fine as a C program but my Sun C++
compiler won't compile it as a C++ program:

#include <stdio.h>
main()
{
   if (1)
      goto gotolab;
   if (2)
      printf("2\n");
   else
gotolab:
      printf("!2\n");
}

CC j.C
"j.C", line 2: error: label gotolab  undefined
Compilation failed

Is this a cfront bug or an undocumented difference between C and C++?

--
-kin

Kin Cho, Principal Engineer (408)980-1590 X230 Fax (408)980-0400
Integrated Systems Inc., 3260 Jay Street, Santa Clara, CA  95054