1. Pradeep Sen
  2. PowerBuilder
  3. Monday, 12 March 2018 00:57 AM UTC

Hi,

I am trying to upgrade a PB 5.0 system to PB 12.6 (will eventually be migrated to 2017, once licence is organised). Yes there are still PB5.0 systems out there.

I am getting errors as "C0174: Type of actual parameter cannot be ancestor of formal reference parameter type.". I can see what the error is but just checking to see if I need to migrate in steps (i.e. maybe migrate to 6.5 or similar before migrating to 12.6).

Thanks in advance.

 

 

Michael Kramer Accepted Answer Pending Moderation
  1. Monday, 12 March 2018 15:15 PM UTC
  2. PowerBuilder
  3. # 1

Hi Pradeep,

No need for intermediate version when migrating PB 5 to newest version. What I would expect as issues when migrating PB5 code:

  • Unicode - as pointed out by Roland
  • Stronger compiler checks - C0174 is one such case.
    • For each version the compiler increased its checks
  • New system defined events, event ID's, and event signatures - EX
    • To support win64/win32, recent PB versions have "longptr" datatype in PBM_CustomXX events, PostEvent(*), TriggerEvent(*), and perhaps a few other places
  • New system classes, controls, and syntax - EX
    • PB 5 is first version with DataStore  and .object notation for DataWindows.
    • Exceptions and TRY-CATCH was introduced in PB 9.
    • PB 5 also introduced custom events with event ID and return-codes from ItemChanged/ItemError.
    • TreeView, ListView, TabControl, and several others
  • PB 5 containing pre-PB 5 coding patterns. EX:
    • ​SetActionCode(...) instead of "return ..."
    • Custom events using PBM_CustomXX despite no intention of having the event called from external apps
    • A hidden window containing DataWindows - which is the pre-PB 5 method of writing DataStores
    • Very shallow inheritance hierarchies because inheritance had been slow in early PB versions
    • VBX control to provide tab controls, tree views, etc. - since PB 5 is first version to implement such controls as PB system controls
  • Obsoleted functionality
    • Biggest impact is "Distributed PowerBuilder" which was excellent peer-to-peer communication
  • Performance considerations -
    • PB 11 (or close to PB 11) the .object notation got fast - a lot faster.
    • Code that was best performing in PB5 may now actually be worse performing.
  • Use of external components
    • You may have difficulty using an outdated VBX/OCX control.
  • Database version compatibility - since you most likely also have to deal with DB drivers being upgraded
    • You may have PB5 app run use an old DB driver that requires updating as well to be supported in current PB.
    • You may also have SQL in DW objects or as embedded SQL that need to change because of DB version

It really is a case-by-case scenario how much rewrite and/or fine tuning is required when you migrate existing code. As Roland points out the Migration Assistant is a good utility to estimate the effort.

 

Good luck,   /Michael

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Roland Smith Accepted Answer Pending Moderation
  1. Monday, 12 March 2018 02:52 AM UTC
  2. PowerBuilder
  3. # 2

You shouldn't need to migrate to an intermediate version. In versions 8 and higher there is a Migration Assistant which you can get to by clicking New and then going to the Tool tab. It will analyze your application and point out things that should be changed.

A major change was in version 10 when Unicode was introduced. String and Char variables are now 2 byte Unicode instead of 1 byte Ansi.

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  1. shoaib siddiqui
  2. Friday, 1 February 2019 18:29 PM UTC
I am having same issue, Migrating PBv10 to R3, in my case it migrated ok, but did not bring the parameters of an event properly, when I try to add parameter manually I get...

C0174: Type of actual parameter cannot be ancestor of formal reference parameter type.



my post: https://community.appeon.com/index.php/qna/q-a/compiler-skipped-some-arguments-in-user-events-during-migration-process

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