Write lock error between linux and windows

@Michael: The programs work great on any DOS network (Lantastic, WFW) or Windows (95, NT, XP, ...).

I created a minimal C program to reproduce the behavior:

#include <io.h>
#include <fcntl.h>
#include <sys\stat.h>
#include <process.h>
#include <share.h>
#include <stdio.h>
#include <conio.h>

int main(void)
{
 int handle, status;
 long length;

 handle = sopen("testlock.txt", O_RDONLY,SH_DENYNO,S_IREAD);

 if (!handle)
 {
    printf("sopen failed\n");
    exit(1);
 }

 length = filelength(handle);
 status = lock(handle,0L,length/2);

 if (status == 0)
    printf("lock succeeded\n");
 else
    printf("lock failed\n");

 printf ("Press a key...\n");
 getch();

 status = unlock(handle,0L,length/2);

 if (status == 0)
    printf("unlock succeeded\n");
 else
    printf("unlock failed\n");

 close(handle);
 return 0;
}

      

        
        
        
      

    

It works fine in DOS / Windows (the first terminal can block, the second cannot), but does not work in Linux under DOSEMU (you can run two instances of the program at the same time on a network share, and both can get blocked regardless of the Linux-Windows / Windows startup sequence -Linux).

This appears to be a known, ongoing problem .

I know that byte locking (like Windows style write locking) requires the latest kernels, although I don't know if this appeared in the 2.4 series or not.

If DosemU can't get you to work, you might have to resort to something more "exotic". Perhaps running FreeDOS under a KVM virtual machine will get you closer to your goals, although you will need to do some manual configuration to get network support (that or figure out how to make a network share as a local drive letter in the guestbook). Scroll through the KVM compatibility list to see the status of the various DOS-like installations.

If you have the original 6.22 installations to work with, then this might be your best bet.