Robert/Steve

Yes C++ does "name mangling" and you need use the extern = "C" directive.

I can invoke C functions from the C++= app using the extern "C" directive.=C2=A0 These C functions are = built into a static library.=C2=A0 The basic steps are - use gcc to compile= the C code to position-independent object code (*.o).=C2=A0 Then create a = library from this object code=C2=A0 - I use "ar r" to create a st= atic library.=C2=A0 Then use g++ to compile the C++ source and link to the = static library.=C2=A0 I could post up the details - but this builds and exe= cutes fine.=C2=A0=C2=A0 I can call the
C functions from a C++ application.=C2=A0

But if I try 'hello.c' found in the VPI sample project for Icaru= s, I get unresolved type link messages when I try the same build method.=C2= =A0 The VPI functions in Icarus are C functions.=C2=A0 According to Icarus = web info - you need to link to the library 'libvpi.a'=C2=A0 - which= I do in the make file.=C2=A0 These errors makes me think my 'libvpi.a&= #39; is not built correctly - the 'libvpi.a' file size is only 1102= bytes.=C2=A0 But I haven't found how to rebuild the 'libvpi.a'= library only.=C2=A0=C2=A0 Guess I could hack the Icarus Makefile, but I th= ought that I may have missed something simple=C2=A0 - so I'm searching = for info on how to rebuild the VPI library for Icarus. =C2=A0

Here's the rub - I don't remember if I installed Ica= rus 0.9.6 from source or with the Linux package manager.=C2=A0 I've use= d Icarus for years and usually I installed from source.=C2=A0 So, there'= ;s a chance I could rebuild Icarus and still have the same problem with the= VPI library.=C2=A0

Lastly, when you try the 'hello' VPI example in Icar= us - it ran OK when I did not link explicitly to the 'libvpi.a' lib= rary
but I used the 'iverilog-vpi' binary.=C2=A0 I wonder if = 9;libvpi.a' has been abandoned or is incomplete and VPI support is only= in 'iverilog-vpi'.=C2=A0

http:/= /iverilog.wikia.com/wiki/Using_VPI

Thanks for your replies= .

Dave W.

On Thu, Jul 3, 2014 at 6:28 PM, Robert Drehm= el <robert AT zoot DOT drehmel DOT com> wrote:

On 07/04/2014 01:22 AM, Stephen R. Besch wrote:
> I know of a few solutions. First, and this is really hard and I would = not recommend it, rewrite the library so it will compile in c++ rather than= C. =C2=A0Second, write a wrapper library in C++ that calls all the functio= ns in C format, or third, tell the C++ compiler that you are calling a &quo= t;C" function so that it won't decorate the names.
>
> Alas, I am not sure exactly how to do this. I know that it involves ei= ther the use of Extern "C" and/or Cdecl, but the exact details fo= r your case you will have to look up.

To be able to call C library functions both from C and C++ code, it's customary to wrap the function declarations in the library header(s)
like that:

"""
#ifdef __cplusplus
extern "C" {
#endif

// function declarations
...

#ifdef __cplusplus
}
#endif
"""

Best regards,
Robert