Ruby and Borland C++

Hello all,

I successfully build ruby using both Borland C++ Builder 6 and BDS2006
C++. However when I try to include ruby.h in my C++ project I get
compiler errors:

[C++ Error] stdio.h(384): E2167 ‘_strerror(const char *)’ was previously
declared with the language ‘C’
[C++ Error] stdio.h(391): E2167 ‘_wperror(const wchar_t *)’ was
previously declared with the language ‘C’
[C++ Error] stdio.h(430): E2167 ‘perror(const char *)’ was previously
declared with the language ‘C’
[C++ Error] stdio.h(447): E2167 ‘strerror(int)’ was previously declared
with the language ‘C’

The debugger jumps into stdio.h file and stops at the line:
using std::_strerror;

If I create pure C project it works just fine. Any ideas how can I get
it work under C++ project? I’ve tried to figure out what causes the
error and looks like it’s coming from win32.h where stdio.h functions
are redeclared.

Sig wrote:

/ …

If I create pure C project it works just fine. Any ideas how can I get
it work under C++ project? I’ve tried to figure out what causes the
error and looks like it’s coming from win32.h where stdio.h functions
are redeclared.

Just based on what you have posted, you need to wrap the ruby.h header
content the same way the C and C++ headers are wrapped.

To avoid double-reading, a typical header file will look like this:

#ifndef UNIQUE_HEADER_NAME
#define UNIQUE_HEADER_NAME

header content goes here

#endif

This arrangement prevents multiple reads of the same header file.

According to the error messages, it seems that the ruby.h file contains
content already read and defined in other header files. One solution is
to
borrow the special defined name from a conflicting header file, and say:

#ifndef UNIQUE_HEADER_NAME
#define UNIQUE_HEADER_NAME
#include ruby.h
#endif

This may be too simple a solution, but it is reasonably clear that a
classic
C/C++ multiple-header-read is happening. You may have to work out a more
complex solution than this example.

Paul L. wrote:

content the same way the C and C++ headers are wrapped.
This arrangement prevents multiple reads of the same header file.
This may be too simple a solution, but it is reasonably clear that a classic
C/C++ multiple-header-read is happening. You may have to work out a more
complex solution than this example.

Thanks Paul for you reply, still I can not solve the problem. I think
this part from win32.h causes the error:

#if defined(__cplusplus)
extern “C++” {
#endif

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <direct.h>
#include <process.h>
#include <time.h>
#include <math.h>
#include <signal.h>
#include <sys/stat.h>
#include <sys/types.h>
#ifdef HAVE_SYS_UTIME_H

include <sys/utime.h>

#else

include <utime.h>

#endif
#include <io.h>
#include <malloc.h>

#if defined(__cplusplus)
}
#endif

Looks like the same headers are defined twice as C++ and as C. Any other
suggestions how to fix that? If I try to redefine them as C I get errors
that types defined in stdio.h don’t exist.

On Fri, Sep 22, 2006 at 02:35:09AM +0900, Sig wrote:

Thanks Paul for you reply, still I can not solve the problem. I think
this part from win32.h causes the error:

#if defined(__cplusplus)
extern “C++” {
#endif

[snip some includes]

#if defined(__cplusplus)
}
#endif

Looks like the same headers are defined twice as C++ and as C. Any other
suggestions how to fix that? If I try to redefine them as C I get errors
that types defined in stdio.h don’t exist.
Hmmm, I’ve never seen extern “C++” before. That whole file looks very MS
compiler specific. I would suggest maybe trying to change it to extern
“C”. Of course that’s just a W.A.G.

Logan C. wrote:

}
#endif

Looks like the same headers are defined twice as C++ and as C. Any other
suggestions how to fix that? If I try to redefine them as C I get errors
that types defined in stdio.h don’t exist.
Hmmm, I’ve never seen extern “C++” before. That whole file looks very MS
compiler specific. I would suggest maybe trying to change it to extern
“C”. Of course that’s just a W.A.G.

Unfortunately it doesn’t help. I just got lost in these redefinitions.

Anyone has a success trying to use ruby with BCB?

Everything compiles just perfectly with MS C++. The problem is we have a
big application written in BCB and now we have to extend it with
scripting. Ruby seems to be a very good choice for that but we ran into
BCB compatibility problems.

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