CODEWITHSUNDEEP
c
user785179
user785179

Reputation: 917

What modern C compiler can I use to build this 1992 MS-DOS program?

I was given the source code to modify an MS-DOS program built back in 1992. I have the EXE file and it runs fine, but I need to modify the source code. The source code needs the below headers to compile. 

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <time.h>
#include <dos.h>
#include <dir.h>
#include <alloc.h>
#include <ctype.h>
#include <string.h>
#include <mem.h>
#include <values.h>

Does anyone know what was used and are there any modern compilers that can handle this? I tried with Visual Studio 2010 and GCC "out of the box", but it fails because some headers are missing (dir.h, alloc.h, mem.h, values.h)

Upvotes: 6

Views: 1227

Answers (6)

Ermac
Ermac

Reputation: 1240

I wasn't able to find a compiler to compile C for MS-DOS directly from Windows 10 as a host, but only from an MS-DOS emulator as a host (which is DOSBox) and the compiler that worked for me was Borland Turbo C++ 3.0. Here are the steps:

  • download DOSBox

  • install it

  • run it you will get a command prompt like Z:\>

  • now back to Windows 10 for preparing a directory dedicated to DOSBox where we will work, for ex create one in your C:\ drive and name it DOS, you can choose another path and name if you want

  • back to DOSBox, in the prompt type:

    Z:\>MOUNT C C:\DOS
Z:\>C:

the first command MOUNT will mount the C:\DOS directory (of your system) for DOSBox, so referencing C:\SOMETHING from inside DOSBox is like referencing a file C:\DOS\SOMETHING from your system. The second command C: will change your prompt to become C:\> like you are pointing into your new C drive (which in turn points to C:\DOS of your system) so typing DIR directly will list files and directories composing it

  • now back to Windows and download Borland Turbo C++ 3.0 zip

  • unzip it inside C:\DOS so you will have C:\DOS\TCC\TURBOC.EXE

  • go back to DOSBox and while in C:\> type:

    C:\>CD TCC
C:\TCC>TURBOC.EXE

this will start the installer, you will get prompted with "some files already exist. Overwrite (y/n)?" so type "y" everytime

  • the installer will create a bunch of files inside TCC that's the compiler files and most importantly we will use TCC.EXE to compile C files

  • back to windows and put a C source file to compile (for ex TEST.C) inside the DOS folder

  • back to DOSBox and still inside TCC folder, type:

    C:\TCC>TCC.exe -I. -L. C:\TEST.C

command explanation: TCC.exe is the compiler executable, -I. is a compiler option to say to use the current directory . as the Include directory, -L. is a compiler option to say to use the current directory . as the Libraries directory and C:\TEST.C is the full path to the C source file to compile

  • the command will generate 2 new files inside TCC folder, TEST.EXE and TEST.OBJ (this is the object file you can delete it if you want), TEST.EXE is the compiled program you can test it by typing TEST.EXE
  • inside Windows you can find it through the files in DOS\TCC that's your executable

Upvotes: 1

Alexey Frunze
Alexey Frunze

Reputation: 62086

There's Turbo C++ 1.01, not so modern, though, that appears to have all these header files as well. I still occasionally use it.

Upvotes: 4

Dmitri
Dmitri

Reputation: 9385

You could try the Open Watcom compiler, which is one of the few relatively up-to-date compilers that builds 16-bit DOS executables. Other than finding an old MS or Borland compiler (or whatever was originally used), that's probably the easiest route.

If you want to rebuild for a different platform instead of rebuilding for DOS again, you'll likely have to make a lot of changes to the program itself. That may be worthwhile, but may be a lot of work and have a lot of surprise headaches.

Upvotes: 5

dmckee --- ex-moderator kitten
dmckee --- ex-moderator kitten

Reputation: 101241

It might be more interesting to ask what what function declarations, type declarations, global variable declarations and macros it needs to have. The particular arrangement of those things into headers isn't very interesting as long as they are all there.

So comment out the offending #includes and let the compiler complain about the bits it is missing. Then you know what you're looking for.

Upvotes: 10

Adrian Cornish
Adrian Cornish

Reputation: 23876

a) Remove all the header files b) Try a compile c) Look up which header file the undefined function/type is int d) Add the header file e) repeat

Upvotes: 1

mpiedrav
mpiedrav

Reputation: 41

You might try using DJGPP. According to the documentation, it may have the headers you need.

Upvotes: 4

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