linking c files with a c++ program

[bg_ie]

Hi all,

To start with, I had 3 c files which I linked using bcc32 -

bcc32 1.c 2.c 3.c

Now I need to convert 1.c to 1.cpp. 1.cpp contains the main function.
The problem is that I now get "Undefined symbol" for any fuction found
in 2.c or 3.c that I try to call from 1.cpp.

I'm guessing the problem is to do with name mangling, but what should I
do exactly to resolve this problem?

Thanks for your help,

Barry.

[Victor Bazarov]

bg***@yahoo.com wrote:

To start with, I had 3 c files which I linked using bcc32 -

bcc32 1.c 2.c 3.c

Now I need to convert 1.c to 1.cpp. 1.cpp contains the main function.
The problem is that I now get "Undefined symbol" for any fuction
found in 2.c or 3.c that I try to call from 1.cpp.

I'm guessing the problem is to do with name mangling, but what should
I do exactly to resolve this problem?

What usually happens is that you change one file to compile with a C++
compiler, but forget to change the declaration of the functions from the
other (C) files to contain 'extern "C"'. The compiler thinks the have
C++ linkage and they don't.

There are two solutions: either change the declarations in the header
files to contain 'extern "C"' _if_ you compile with a C++ compiler:

---- some header included in both C and C++ sources:

#ifdef __cplusplus
extern "C" {
#endif

int foo(void);
void bar(int);

#ifdef __cplusplus
}
#endif

------------------------------

*or* compile _all_ files now using a C++ compiler.

V
--
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[Greg Comeau]

In article <11**********************@m79g2000cwm.googlegroups .com>,
<bg***@yahoo.comwrote:

>To start with, I had 3 c files which I linked using bcc32 -

bcc32 1.c 2.c 3.c

Now I need to convert 1.c to 1.cpp. 1.cpp contains the main function.
The problem is that I now get "Undefined symbol" for any fuction found
in 2.c or 3.c that I try to call from 1.cpp.

I'm guessing the problem is to do with name mangling, but what should I
do exactly to resolve this problem?

This is one direct answer to your question:

http://www.comeaucomputing.com/techtalk/#externc

It's unclear whether it is necessary in your case though
because your do not say why are orchestrating your code this way,
so maybe there is some other alternative (compiling everything in C++
etc) if you give those details.
--
Greg Comeau / 20 years of Comeauity! Intel Mac Port now in alpha!
Comeau C/C++ ONLINE == http://www.comeaucomputing.com/tryitout
World Class Compilers: Breathtaking C++, Amazing C99, Fabulous C90.
Comeau C/C++ with Dinkumware's Libraries... Have you tried it?

[bg_ie]

Greg Comeau wrote:

In article <11**********************@m79g2000cwm.googlegroups .com>,
<bg***@yahoo.comwrote:

To start with, I had 3 c files which I linked using bcc32 -

bcc32 1.c 2.c 3.c

Now I need to convert 1.c to 1.cpp. 1.cpp contains the main function.
The problem is that I now get "Undefined symbol" for any fuction found
in 2.c or 3.c that I try to call from 1.cpp.

I'm guessing the problem is to do with name mangling, but what should I
do exactly to resolve this problem?

This is one direct answer to your question:

http://www.comeaucomputing.com/techtalk/#externc

It's unclear whether it is necessary in your case though
because your do not say why are orchestrating your code this way,
so maybe there is some other alternative (compiling everything in C++
etc) if you give those details.
--
Greg Comeau / 20 years of Comeauity! Intel Mac Port now in alpha!
Comeau C/C++ ONLINE == http://www.comeaucomputing.com/tryitout
World Class Compilers: Breathtaking C++, Amazing C99, Fabulous C90.
Comeau C/C++ with Dinkumware's Libraries... Have you tried it?

Thanks for your help!