1 files changed, 91 insertions, 0 deletions
diff --git a/reference/C/CONTRIB/SNIP/prtoggle.c b/reference/C/CONTRIB/SNIP/prtoggle.c
new file mode 100755
index 0000000..127a1fc
--- /dev/null
+++ b/reference/C/CONTRIB/SNIP/prtoggle.c
@@ -0,0 +1,91 @@
+/*
+**  prtoggle()
+**
+**  Tee's all standard output to the printer.
+**
+**  Parameters: None
+**
+**  Returns:  0 if operation was successful.
+**           -1 if stdout or stdin is redirected.
+**
+**  Side effects: Flushes the keyboard buffer
+**
+**  Original Copyright 1988-1991 by Bob Stout as part of
+**  the MicroFirm Function Library (MFL)
+**
+**  This subset version is functionally identical to the
+**  version originally published by the author in Tech Specialist
+**  magazine and is hereby donated to the public domain.
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <conio.h>
+#include <io.h>
+
+#if !defined(__ZTC__) && !defined(__TURBOC__)
+ #define MK_FP(seg,offset) \
+        ((void far *)(((unsigned long)(seg)<<16) | (unsigned)(offset)))
+ #define peek(s,o) (*((unsigned far *)(MK_FP(s,o))))
+ #define poke(s,o,w) (*((unsigned far *)(MK_FP(s,o)))=(w))
+#endif
+
+#define SUCCESS 0
+#define ERROR -1
+
+static unsigned head, tail, start, end;
+static int idx = 0;
+static unsigned keystack[16][2];
+
+int ungetkey(unsigned key)
+{
+        int count;
+
+#ifdef __ZTC__
+        peek(0x40, 0x1a, &head, sizeof(unsigned));
+        peek(0x40, 0x1c, &tail, sizeof(unsigned));
+#else
+        head = peek(0x40, 0x1a);
+        tail = peek(0x40, 0x1c);
+#endif
+        count = tail - head;
+        if (0 > count)
+                count += (16 * sizeof(unsigned));
+        count >>= 1;
+
+        if (15 > count)
+        {
+#ifdef __ZTC__
+                peek(0x40, tail, &keystack[idx][0], sizeof(unsigned));
+#else
+                keystack[idx][0] = peek(0x40, tail);
+#endif
+                keystack[idx][1] = tail;
+#ifdef __ZTC__
+                poke(0x40, tail, &key, sizeof(unsigned));
+#else
+                poke(0x40, tail, key);
+#endif
+                tail += sizeof(unsigned);
+                if (0x3e <= tail)
+                        tail = 0x1e;
+#ifdef __ZTC__
+                poke(0x40, 0x1c, &tail, sizeof(unsigned));
+#else
+                poke(0x40, 0x1c, tail);
+#endif
+                return key;
+        }
+        return EOF;
+}
+
+int prtoggle(void)
+{
+      if (!isatty(fileno(stdin)) || !isatty(fileno(stdout)))
+            return -1;
+      while (kbhit())           /* Flush the keyboard buffer            */
+            getch();
+      ungetkey('P' - 64);       /* Stuff a Ctrl-P into the buffer       */
+      system("");               /* Let COMMAND.COM do the work          */
+      return 0;
+}