Commit 39788793 for tesseract

commit 397887939a357f166f4674bc1d66bb155795f325
Author: Eduardo Mozart de Oliveira <2974895+eduardomozart@users.noreply.github.com>
Date:   Sat Feb 21 06:05:50 2026 -0300

    Correct mutex call to prevent multiple instances (#4517)

diff --git a/nsis/tesseract.nsi b/nsis/tesseract.nsi
index 077c23f2..af28a9b5 100644
--- a/nsis/tesseract.nsi
+++ b/nsis/tesseract.nsi
@@ -16,7 +16,6 @@
 ; https://nsis.sourceforge.io/Docs/Modern%20UI%202/Readme.html

 ; TODO:
-; * Fix PreventMultipleInstances.
 ; * Add Tesseract icon and images for installer.

 SetCompressor /FINAL /SOLID lzma
@@ -1456,12 +1455,13 @@ FunctionEnd

 ; Prevent running multiple instances of the installer
 Function PreventMultipleInstances
-  ; TODO: Does not work.
   Push $R0
-  System::Call 'kernel32::CreateMutexA(i 0, i 0, t ${PRODUCT_NAME}) ?e'
+  System::Call 'kernel32::CreateMutex(p 0, i 0, t "${PRODUCT_NAME}") p .r1 ?e'
   Pop $R0
-  StrCmp $R0 0 +3
+  ; 183 is the Windows error code for ERROR_ALREADY_EXISTS
+  StrCmp $R0 183 0 +4
     MessageBox MB_OK|MB_ICONEXCLAMATION "The installer is already running." /SD IDOK
+    Pop $R0
     Abort
   Pop $R0
 FunctionEnd