disable, _disable, enable, _enable

Disables and enables interrupts.

Defined in header <dos.h>

Syntax

#include <dos.h>
void disable(void);
void _disable(void);
void enable(void);
void _enable(void);

Portability

Remarks

These macros are designed to provide a programmer with flexible hardware interrupt control.

The disable and _disable macros disable interrupts. Only the NMI (non-maskable interrupt) is allowed from any external device.

The enable and _enable macros enable interrupts, allowing any device interrupts to occur.

Return value

None.

See also

• getvect

Example

/* This is an interrupt service routine. You  cannot compile this program with
   Test Stack Overflow turned on and get an executable  file that operates
   correctly. */
#include <stdio.h>
#include <dos.h>
#include <conio.h>
Mefine  INTR OXlC  /* The clock tick interrupt  */

#ifdef   cplusplus
    #def ine _CPPARGS  ...
#else
    Mefine  _CPPARGS
#endif

void interrupt  (*oldhandler) {_CPPARGS) ;

int count=0;
void interrupt handler ( CPPARGS)  /* if C++, need the the ellipsis */
{
   /* disable interrupts during the handling of the  interrupt */
   _disable();
   /* increase the global counter */
   count++;
   /* reenable interrupts at the end of the handler  */
   enable();
   /* call the old routine */
   oldhandler 0;
}
int main(void)

   /* save the old interrupt vector */
   oldhandler = _dos_getvect (INTR);
   /* install the new interrupt handler */
   _dos_setvect(INTR, handler);

   /* loop until the counter exceeds 20 */
   while (count < 20)
      printf("count is %d\n",count);

   /* reset the old interrupt handler */
   _dos_setvect(INTR, oldhandler);
return

Differences from modern implementations

Nothing recorded yet.

Modern references

• Microsoft C runtime (search)

These are search links, not yet checked by hand.

Extraction notes

• heading `disable, disable, enable, enable` read as `disable, _disable, enable, _enable`

Stable link: /3.1/dos.h/disable/ · short form /3.1/disable/