From 2ed14816feaf2af519d97800b15ac3798ff695e3 Mon Sep 17 00:00:00 2001
From: Richard Burgess <>
Date: Sat, 21 Jan 1995 07:59:46 +0000
Subject: [PATCH] autocommit for file dated 1995-01-21 07:59:46

---
 msamples/service/service.c | 95 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 95 insertions(+)
 create mode 100644 msamples/service/service.c

diff --git a/msamples/service/service.c b/msamples/service/service.c
new file mode 100644
index 0000000..a5f48b5
--- /dev/null
+++ b/msamples/service/service.c
@@ -0,0 +1,95 @@
+/* Super Simple System Service.
+   This is expanded from the sample in the Systems Programming
+   chapter to show how to properly deinstall a system service.
+   The steps to deinstall are:
+   1) UnRegister the Service
+   2) Serve all remaining requests at service exchange
+   3) Deallocate all resources
+   4) Exit
+*/
+
+#include <stdio.h>
+#include "\OSSource\MKernel.h"
+#include "\OSSource\MJob.h"
+#include "\OSSource\MVid.h"
+
+#define ErcOK         0
+#define ErcOpCancel   4
+#define ErcNoSuchSvc  30
+#define ErcBadSvcCode 32
+
+struct RqBlkType *pRqBlk;        /* A pointer to a Reqeust Block */
+unsigned long NextNumber = 0;    /* The number to return */
+unsigned long MainExch;          /* Where we wait for Requests */
+unsigned long Message[2];        /* The Message with the Request */
+long rqHndl;				 /* Used for keyboard request */
+
+void main(void)
+{
+unsigned long OSError, ErrorToUser, keycode;
+long *pDataRet;
+
+  OSError = AllocExch(&MainExch);	  /* get an exchange */
+
+  if (OSError)                      /* look for a kernel error */
+    ExitJob(OSError);
+
+  OSError = RegisterSvc("NUMBERS ", MainExch);
+
+  if (OSError)                      /* look for a system error */
+    ExitJob(OSError);
+
+  SetNormVid(WHITE|BGBLACK);
+  ClrScr();
+
+  printf("NUMBERS Service Installed.\r\n");
+  printf("ANY valid keystroke will terminate the service.\r\n");
+
+  OSError = Request("KEYBOARD", 1, MainExch, &rqHndl, 0, &keycode,
+   					  4, 0, 0, 1, 0, 0);  /* 1 in dData0 = WAIT for key */
+  if (OSError)
+	  printf("Error on Keyboard Request:\r\n", OSError);
+
+  while (1)  		/* WHILE forever (almost...) */
+  {
+
+	/* Now we wait for a client or for a keystroke to come back */
+
+    OSError = WaitMsg(MainExch, Message); /* Exch & pointer */
+
+    if (!OSError)
+    {
+
+	  if (Message[0] == rqHndl)  /* it was a keystroke and NOT a client */
+	  {
+		UnRegisterSvc("NUMBERS ");
+		while (!CheckMsg(MainExch, Message))
+		{
+            pRqBlk = Message[0];
+			Respond(pRqBlk, ErcNoSuchSvc);
+		}
+		DeAllocExch(MainExch);
+		ExitJob(ErcOpCancel);
+	  }
+
+      pRqBlk = Message[0];   /* First DWORD contains ptr to RqBlk */
+
+	  if (pRqBlk->ServiceCode == 0)          /* Abort request from OS */
+          ErrorToUser = ErcOK;
+
+      else if (pRqBlk->ServiceCode == 1)     /* User Asking for Number */
+      {
+		 pDataRet = pRqBlk->pData1;
+         *pDataRet = NextNumber++;       /* Give them a number */
+         ErrorToUser = ErcOK;                 /* Respond with No error */
+
+		printf("NUMBERS Service gave out number: %d.\r\n", NextNumber-1);
+
+      }
+      else ErrorToUser = ErcBadSvcCode;       /* Unknown Service code! */
+
+      OSError = Respond(pRqBlk, ErrorToUser); /* Respond to Request */
+
+    }
+  }  /* Loop while(1) */
+}
-- 
2.40.0