--- parser3/src/main/pa_os.C	2017/01/29 19:41:17	1.17
+++ parser3/src/main/pa_os.C	2026/04/25 13:38:46	1.26
@@ -1,20 +1,62 @@
 /** @file
 	Parser: commonly functions.
 
-	Copyright (c) 2001-2015 Art. Lebedev Studio (http://www.artlebedev.com)
-	Author: Alexandr Petrosian <paf@design.ru> (http://paf.design.ru)
+	Copyright (c) 2001-2026 Art. Lebedev Studio (https://www.artlebedev.com)
+	Authors: Konstantin Morshnev <moko@design.ru>, Alexandr Petrosian <paf@design.ru>
 */
 
 #include "pa_config_includes.h"
 #include "pa_os.h"
 
-volatile const char * IDENT_PA_OS_C="$Id: pa_os.C,v 1.17 2017/01/29 19:41:17 moko Exp $" IDENT_PA_OS_H; 
+volatile const char * IDENT_PA_OS_C="$Id: pa_os.C,v 1.26 2026/04/25 13:38:46 moko Exp $" IDENT_PA_OS_H; 
 
 unsigned int pa_lock_attempts=PA_LOCK_ATTEMPTS;
 
 #ifdef _MSC_VER
 #include <windows.h>
-#endif
+
+#define PA_SH_LOCK 2
+#define PA_EX_LOCK 1
+#define PA_ULOCK 0
+#define FLOCK(operation) int status=pa_flock(fd, operation);
+#define ERRNO pa_errno()
+
+int pa_flock(int fd, int operation) {
+    HANDLE hFile = (HANDLE)_get_osfhandle(fd);
+    if (hFile == INVALID_HANDLE_VALUE) {
+        return -1;
+    }
+
+    OVERLAPPED overlapped = {0};
+
+    if (operation == PA_ULOCK) {
+        return UnlockFileEx(hFile, 0, MAXDWORD, MAXDWORD, &overlapped) ? 0 : -1;
+    } else {
+        DWORD flags = LOCKFILE_FAIL_IMMEDIATELY;
+        if (operation == PA_EX_LOCK) {
+            flags |= LOCKFILE_EXCLUSIVE_LOCK;
+        }
+        return LockFileEx(hFile, flags, 0, MAXDWORD, MAXDWORD, &overlapped) ? 0 : -1;
+    }
+}
+
+int pa_errno() {
+    switch(GetLastError()) {
+        case ERROR_LOCK_VIOLATION: // real case: returning the same error as with _locking
+            return EACCES;
+        case ERROR_IO_PENDING:
+            return EAGAIN;
+        case ERROR_INVALID_HANDLE:
+            return EBADF;
+        case ERROR_NOT_LOCKED:
+            return ENOLCK;
+    }
+    return EACCES;
+}
+
+#else
+
+#define ERRNO errno
 
 #ifdef HAVE_FLOCK
 
@@ -24,14 +66,6 @@ unsigned int pa_lock_attempts=PA_LOCK_AT
 #define FLOCK(operation) int status=flock(fd, operation);
 
 #else
-#ifdef HAVE__LOCKING
-
-#define PA_SH_LOCK _LK_NBLCK
-#define PA_EX_LOCK _LK_NBLCK
-#define PA_ULOCK _LK_UNLCK
-#define FLOCK(operation) lseek(fd, 0, SEEK_SET); int status=_locking(fd, operation, 1);
-
-#else
 #ifdef HAVE_FCNTL
 
 #define PA_SH_LOCK F_RDLCK
@@ -54,6 +88,7 @@ unsigned int pa_lock_attempts=PA_LOCK_AT
 #endif
 #endif
 #endif
+
 #endif
 
 int pa_lock(int fd, int attempts, int operation){
@@ -62,7 +97,7 @@ int pa_lock(int fd, int attempts, int op
 		if(status==0)
 			return 0;
 		if(--attempts<=0)
-			return errno;
+			return ERRNO;
 		pa_sleep(PA_LOCK_WAIT_TIMEOUT_SECS, PA_LOCK_WAIT_TIMEOUT_USECS);
 	}
 };