Improvements in threadtest.c (for Unix) and some minor bug fixes that result

from the better testing. (CVS 776)

FossilOrigin-Name: 326e0983c34b584a3c4a2300399bff0a8281b9f8

src/main.c

@@ -14,7 +14,7 @@
 ** other files are for internal use by SQLite and should not be
 ** accessed by users of the library.
 **
-** $Id: main.c,v 1.102 2002/09/05 23:21:37 drh Exp $
+** $Id: main.c,v 1.103 2002/11/01 01:55:37 drh Exp $
 */
 #include "sqliteInt.h"
 #include "os.h"
@@ -613,6 +613,10 @@ int sqlite_exec(
       sqliteSafetyOff(db);
       return rc;
     }
+    if( pzErrMsg ){
+      sqliteFree(*pzErrMsg);
+      *pzErrMsg = 0;
+    }
   }
   if( db->file_format<3 ){
     sqliteSafetyOff(db);