Q12012: Getting to the Mouse from a Real-Mode C Program

Article: Q12012
Product(s): See article
Version(s): 3.00 4.00 5.00 6.00 6.00a
Operating System(s): MS-DOS
Keyword(s): ENDUSER | | mspl13_c
Last Modified: 6-FEB-1991

Question:

I am trying to access the mouse from a C program. Do you have an
example to help get me started?

Response:

Below is a program example to test mouse usage from a C program. The
mouse driver must be installed first. This type of information is
described in the "Mouse Programming Interface" chapter of the
"Microsoft Mouse Programmer's Reference" available from Microsoft
Press.

Sample Code
-----------

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

int m1=0,m2=0,m3=0,m4=0;
union REGS Mouse_regs;

void mouse(void)
{
    Mouse_regs.x.ax=m1;
    Mouse_regs.x.bx=m2;
    Mouse_regs.x.cx=m3;
    Mouse_regs.x.dx=m4;
    int86(0x33,&Mouse_regs,&Mouse_regs);
    m1=Mouse_regs.x.ax;
    m2=Mouse_regs.x.bx;
    m3=Mouse_regs.x.cx;
    m4=Mouse_regs.x.dx;
}

void main(void)
{
    /* Turn on the mouse */
    m1 = 1;           /* SHOW MOUSE Opcode -- See reference */
    m2 = m3 = m4 = 0; /* Additional parameters (init=0) */
    mouse();          /* Make it happen */

    for (;;)          /* loop until both buttons are down */
       {
        m1=3;         /* Get mouse status */
        m2=m3=m4=0;
        mouse();

        if (m2 & 1)
           printf("Left button down\n");
        if (m2 & 2)
           printf("Right button down\n");
        if (m2 & 1 && m2 & 2)
           {
            printf("BOTH!\n");
            exit(0);
           }
       }
}

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