From e611b132f9b8abe35b362e5870b74bce94a1e58e Mon Sep 17 00:00:00 2001
From: Adam <you@example.com>
Date: Sat, 16 May 2020 20:51:50 -0700
Subject: initial commit

---
 private/nw/test/lock.c | 80 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)
 create mode 100644 private/nw/test/lock.c

(limited to 'private/nw/test/lock.c')

diff --git a/private/nw/test/lock.c b/private/nw/test/lock.c
new file mode 100644
index 000000000..89eb4d4b2
--- /dev/null
+++ b/private/nw/test/lock.c
@@ -0,0 +1,80 @@
+
+
+/* LOCKING.C: This program opens a file with sharing. It locks
+
+ * some bytes before reading them, then unlocks them. Note that the
+ * program works correctly only if the following conditions are met:
+ *     - The file exists
+ *     - The program is run with MS-DOS version 3.0 or later
+ *       with file sharing installed (SHARE.COM or SHARE.EXE), or
+ *       if a Microsoft Networks compatible network is running
+
+ */
+
+#include <crt\io.h>
+#include <sys\types.h>
+#include <sys\stat.h>
+#include <sys\locking.h>
+#include <share.h>
+#include <fcntl.h>
+#include <stdio.h>
+
+#include <stdlib.h>
+
+#define STRING "0123456789012345678901234567890123456789012345678"
+
+void
+_cdecl
+main( void )
+{
+   int  fh, numread;
+
+   char buffer[60];
+   /* Quit if can't open file or MS-DOS version doesn't support sharing. */
+   fh = _sopen( "test.txt",
+                 _O_CREAT | _O_TRUNC | _O_RDWR,
+                 _SH_DENYNO,
+                 _S_IREAD | _S_IWRITE );
+
+   if( (fh == -1) || (_osmajor < 3) ) {
+      printf( "Cannot create/open file\n" );
+      exit( 1 );
+   }
+
+    _write( fh, STRING, sizeof(STRING));
+    _write( fh, STRING, sizeof(STRING));
+    _write( fh, STRING, sizeof(STRING));
+    _write( fh, STRING, sizeof(STRING));
+    _write( fh, STRING, sizeof(STRING));
+    _write( fh, STRING, sizeof(STRING));
+
+   /* Lock some bytes and read them. Then unlock. */
+   lseek( fh, 0L, SEEK_SET );
+   if( _locking( fh, LK_NBLCK, 50L ) != -1 )
+   {
+      printf( "No one can change these bytes while I'm reading them\n" );
+      numread = _read( fh, buffer, 50 );
+      printf( "%d bytes read: %.50s\n", numread, buffer );
+      lseek( fh, 0L, SEEK_SET );
+     _locking( fh, LK_UNLCK, 50L );
+      printf( "Now I'm done. Do what you will with them\n" );
+   }
+   else
+
+      perror( "Locking failed\n" );
+
+   lseek( fh, 4096L, SEEK_SET );
+   if( _locking( fh, LK_NBLCK, 1024L ) != -1 )
+   {
+      printf( "The lock off the end of the file worked ok\n" );
+      //lseek( fh, 4096L, SEEK_SET );
+     if( _locking( fh, LK_UNLCK, 1024L ) == -1 )
+      printf( "The second unlock failed\n" );
+   }
+   else
+
+      perror( "Locking failed\n" );
+
+   _close( fh );
+}
+
-- 
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