C Program to check if mouse support is available or not.

#include<stdio.h>
#include<conio.h>
#include<dos.h>

int initmouse();

union REGS i, o;

int main()
{
   int flag;

   flag = initmouse();

   if ( flag == 0 )
      printf("\nMouse support not available.");
   else
      printf("\nMouse support available.");

   getch();
   return 0;
}

int initmouse()
{
   i.x.ax = 0;
   int86(0X33,&i,&o);
   return ( o.x.ax );
}

Output :

Mouse support available.

Explanation :
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• Int86() is a C function that allows to call interrupts in the C program
• Header File : dos.h

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Usage is int86 (int intr num, union REGS *inregs,
                                  union REGS *outregs)

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• In and out register must be type of REGS.
• REGS is a built in UNION declaration in C.
• It is defined in the header file

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