Hi, Oreste -

API functions calls can be different in 64-bit, because the datatypes Windows uses for some values (like pointers and handles, for example) are 64-bit instead of 32-bit.

Here is the external function declaration (EFD) you should use for the GetSubMenu WinAPI function:

FUNCTION Longptr GetSubMenu ( &
   Longptr hMenu, &
   Long    nPos &
   ) LIBRARY "user32.dll"

If you are not familiar with the Longptr datatype, it gets translated during compile-time to either a Long (32-bit) or LongLong (64-bit). Obviously, you then have to change the code that calls the external function to use the appropriate datatypes.

I've written a four-part tutorial about interfacing PB to the Windows API, which is available in Tech Articles section of the Articles & Blogs portion of the Appeon Community web site, if you're interested.

Regards, John

64-bit project cannot use 32-bit DLLs, and this generally applies to everything.  For example, you must use 64-bit DB driver for 64-bit compiled app.

I don't think it is trivial undertaking to migrate existing project to 64-bit, but if you really want to do it John's Tech Articles are useful.  You should also be looking at the product documentation and the Elevate tech session regarding 64-bit migration. 

Here are the various links:

• 64-bit Elevate session
  • https://www.appeon.com/developers/library/videos/migrating-powerbuilder-desktop-apps-64-bit.html
• Product documentation
  
  • https://docs.appeon.com/pb2019r3/application_techniques/ch09s03.html
• John's Win API tech articles
  • Part 1- https://community.appeon.com/index.php/articles-blogs/tutorials-articles/2-powerbuilder/302-interfacing-pb-applications-with-the-windows-api-part-1
  • Part 2 - https://community.appeon.com/index.php/articles-blogs/tutorials-articles/2-powerbuilder/303-interfacing-pb-applications-with-the-windows-api-part-2
  • Part 3 - https://community.appeon.com/index.php/articles-blogs/tutorials-articles/2-powerbuilder/304-interfacing-pb-applications-with-the-windows-api-part-3
  • Part 4 - https://community.appeon.com/index.php/articles-blogs/tutorials-articles/2-powerbuilder/305-interfacing-pb-applications-with-the-windows-api-part-4