Step by Step solution about How to resolve the algorithm Keyboard macros step by step in the C programming language

The code you provided is a simple X11 program that listen for the F7 and F6 keys being pressed. It use the XLib library to interact with the X Window System , and the keysym.h header to map key codes to symbols.

The main function first calls XOpenDisplay to open a connection to the X server.

If the connection is successful , it calls XGrabKey to grab the F7 and F6 keys .

The Mod1Mask argument specifies that the keys should be grabbed when the Alt key is pressed .

The DefaultRootWindow(d) argument specifies that the keys should be grabbed on the root window of the screen. The True argument specifies that the keys should be grabbed asynchronously, which means that the program will not wait for the keys to be released before continuing.

The for loop then enters an event loop, waiting for events to occur. When an event occurs , the program calls XNextEvent to retrieve the event.

If the event is a key press event, the program calls XLookupKeysym to translate the key code to a key symbol.

If the key symbol is XK_F7 , the program prints a message to the standard output.

If the key symbol is XK_F6, the program breaks out of the event loop.

Finally, the program calls XUngrabKey to ungrab the F7 and F6 keys , and then calls XCloseDisplay to close the connection to the X server.

#include <stdio.h>
#include <stdlib.h>
#include <X11/Xlib.h>
#include <X11/keysym.h>

int main()
{
  Display *d;
  XEvent event;
  
  d = XOpenDisplay(NULL);
  if ( d != NULL ) {
                /* or simply XK_F7 should work too */
    XGrabKey(d, XKeysymToKeycode(d, XStringToKeysym("F7")), 
	     Mod1Mask, /* normally it's Alt */ 
	     DefaultRootWindow(d), True, GrabModeAsync, GrabModeAsync);
    XGrabKey(d, XKeysymToKeycode(d, XStringToKeysym("F6")), 
	     Mod1Mask, 
	     DefaultRootWindow(d), True, GrabModeAsync, GrabModeAsync);

    for(;;)
    {
      XNextEvent(d, &event);
      if ( event.type == KeyPress ) {
	KeySym s = XLookupKeysym(&event.xkey, 0);
	if ( s == XK_F7 ) {
	  printf("something's happened\n");
	} else if ( s == XK_F6 ) {
	  break;
	}
      }
    }

    XUngrabKey(d, XKeysymToKeycode(d, XStringToKeysym("F7")), Mod1Mask, DefaultRootWindow(d));
    XUngrabKey(d, XKeysymToKeycode(d, XStringToKeysym("F6")), Mod1Mask, DefaultRootWindow(d));
  }
  return EXIT_SUCCESS;
}