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diff --git a/reference/C/CONTRIB/SNIP/keywatch.c b/reference/C/CONTRIB/SNIP/keywatch.c
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+++ b/reference/C/CONTRIB/SNIP/keywatch.c
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+/* keywatch.c 12-29-91 Robert Mashlan, Public Domain                *\
+
+   DOS compiler portability modifications added by Bob Stout,
+   1:106/2000.6
+
+   This program monitors the keyboard interrupt, and stores the
+   status of each key as to whether it is pressed or released.
+
+   This is done by capturing interrupt 9, and watching the make/break
+   codes.  The status is updated in the keys array, where 1 means
+   that the key is pressed, while 0 means the key is released.  The
+   key array is uses the scan code for an index instead of the ascii
+   character.  It is simple enough to find the scan code for a key,
+   just run this program and watch the display.
+
+   The ekeys array will reflect the status of keys found on an AT
+   keyboard.  For instance, the left and right alt keys are
+   differentiated, as well as the edit control keys on the numeric
+   keypad and the one not on the numeric keypad.
+
+   Since this program installs an interrupt handler, it should be
+   terminated normally, such the keyboard handler can be removed.
+   The ^C/^Break exit is captured via signal(), but all possible
+   exits should be trapped.
+
+\*                                                                  */
+
+#include <stdio.h>
+#include <dos.h>
+#include <conio.h>
+#include <signal.h>
+
+#define BYTE unsigned char
+#if defined(__TURBOC__)
+ #define _interrupt interrupt
+ #define _far far
+ #define IN_PORT(port)           inportb(port)
+ #define IN_PORTW(port)          inport(port)
+ #define OUT_PORT(port, val)     outportb(port, val)
+ #define OUT_PORTW(port, val)    outport(port, val)
+#else
+ #if defined(__ZTC__)
+  #include <int.h>
+ #else /* MSC, QC, Watcom */
+  #define getvect(n) _dos_getvect(n)
+  #define setvect(n,v) _dos_setvect(n,v)
+ #endif
+ #define IN_PORT(port)           inp(port)
+ #define IN_PORTW(port)          inpw(port)
+ #define OUT_PORT(port, val)     outp(port, val)
+ #define OUT_PORTW(port, val)    outpw(port, val)
+#endif
+
+volatile char keys[128];           /* array of key states           */
+volatile char ekeys[128];          /* array of AT key states        */
+
+#define KEYPORT        0x60        /* keyboard scan code port       */
+#define keyport()      IN_PORT(KEYPORT)
+        /* macro that returns the scancode of the key that caused   */
+        /* the interrupt                                            */
+
+/* Define:                                                          *\
+
+   installisr()
+         installation macro, installs newkbisr() in the keyboard
+         interrupt chain
+
+   removeisr()
+         removal macro, call to remove newkbisr() from interrupt
+         chain.  oldkbisr()  must be removed before program ends
+\*                                                                  */
+
+#ifdef __ZTC__
+ #define installisr() int_intercept(0x09, newkbisr, 0)
+ #define removeisr()  int_restore(0x09);
+#else
+ #define installisr()  (oldkbisr=getvect(0x09),setvect(0x09,newkbisr))
+ #define removeisr()   setvect(0x09,oldkbisr)
+ #ifdef __TURBOC__
+  void _interrupt (_far *oldkbisr)(void);    /* address of old ISR   */
+ #else
+  void (_interrupt _far *oldkbisr)(void);    /* address of old ISR   */
+ #endif
+#endif
+
+#ifdef __ZTC__
+ int newkbisr(struct INT_DATA *pd)
+#elif defined(__TURBOC__)
+ void _interrupt newkbisr(void)
+#else
+ void _interrupt _far newkbisr(void)
+#endif
+{
+      static extkey;
+      BYTE scancode = (BYTE)keyport();         /* read keyboard scan code */
+
+      if (scancode == 0xe0)
+            extkey = 1;               /* use ekey array on next scan code */
+      else
+      {
+            if (scancode & 0x80)                          /* key released */
+                  (extkey ? ekeys : keys)[scancode & 0x7f] = 0;
+            else  (extkey ? ekeys : keys)[scancode] = 1;
+            extkey = 0;
+      }
+
+#ifdef __ZTC__
+      return 0;                         /* chain to previous keyboard ISR */
+#else
+      oldkbisr();                       /* chain to previous keyboard ISR */
+#endif
+}
+
+int keyspressed(void)           /* returns number of keys being held down */
+{
+      int i, result = 0;
+
+      for (i = 0; i < 128; i++)
+      {
+            result += keys[i];
+            result += ekeys[i];
+      }
+      return result;
+}
+
+int main(void)
+{
+      int lastkeycount = 0;
+
+      signal(SIGINT,SIG_IGN);  /* ingnore ^C and ^Break */
+      installisr();            /* install interrupt handler */
+      while(1)
+      {
+            int i;
+
+            if (keyspressed() != lastkeycount) /* change in keystatus */
+            {
+                  lastkeycount = keyspressed();
+                  puts("---");
+                  for(i = 0; i < 128; i++)
+                  {
+                        if (keys[i])
+                              printf("key with scan code %02x "
+                                    "has been pressed\n", i);
+                        if (ekeys[i])
+                              printf("key with scan codes e0 %02x "
+                                    "had been pressed\n", i);
+                  }
+            }
+            if (kbhit() && getch()==0x1b) /* terminate when Esc pressed */
+                  break;
+      }
+      removeisr();   /* remove interrupt handler */
+      return 0;
+}