What does "union REGS reg;" mean 2

[marcasii]

Hi,

I am a C++ novice having worked with it for only a short while years ago. I now have been given a c++ file that runs a simple racing timing application (DOS based). I am trying to compile it now using Borland C++ compiler and get the error (plus many more but all relate to this one):

Error E2450 test.cpp 63: Undefined structure 'REGS'
Error E2450 test.cpp 63: Undefined structure 'REGS'

The line it refers to is simply:
union REGS reg;

I am unsure what union or reg is in C++

the command line I use to compile is:
bcc32 -Ld:\borland\bcc55\lib -Id:\borland\BCC55\include test.cpp

Any ideas why it is having a problem with this line?

 

[2ffat]

REGS is a structure, e.g.,

struct REGS
{
    double One;
    int Two;
    string Three;
}

The error indicates that the structure isn't defined in your code. Did you forget to include a file?

James P. Cottingham

^{There's no place like 127.0.0.1.
There's no place like 127.0.0.1.}

 

[lionelhill]

regs is usually a predefined structure to access the processor's registers. If you are adapting 16-bit code for a 32-bit environment it's nearly certain that the use the original programmer made of the processor's registers will not be acceptable in your new code. Unfortunately this is the sort of hardware-near thing that is often hard to translate unless you understand what it's doing.

 

[marcasii]

Yeah that was it, I needed a 16bit compiler.

Thanks.