PureBasic Forums - English

Posted: **Tue May 21, 2024 3:40 am**

Is there a trick to determine if UseSQLiteDatabase() has already been called?

I have a module that uses sqlite internally, and I don't want to re-issue UseSQLiteDatabase() again if the main code has already called it.

Posted: **Tue May 21, 2024 4:38 am**

Isn't that just a directive to link it?
but if it causes any odd side effects you could use a macro

Code: Select all

Global usesqlite 
Procedure _UseSQLiteDatabase()  
  If Not usesqlite 
    usesqlite = UseSQLiteDatabase() 
  Else 
    Debug "in use" 
  EndIf 
EndProcedure   

Macro UseSQLiteDatabase() 
  _UseSQLiteDatabase() 
EndMacro 

UseSQLiteDatabase()  
UseSQLiteDatabase()

Posted: **Tue May 21, 2024 4:45 am**

I had the same question
https://www.purebasic.fr/english/viewtopic.php?p=619675

Short answer: no you can't

Posted: **Tue May 21, 2024 1:28 pm**

Why not calling it again ? If it's already called, it just does nothing.

Posted: **Tue May 21, 2024 6:18 pm**

In my case I want to activate features which is only needed if there is UseSQLiteDatabase() called. But most the time it is not necessary.

Posted: **Tue May 21, 2024 7:21 pm**

Fred wrote: Tue May 21, 2024 1:28 pm Why not calling it again ? If it's already called, it just does nothing.

You need a different version of sqlite's DLL

Code: Select all


UseSQLiteDatabase("c:\pbincludes\sqlite3.dll")
h2=OpenDatabase(-1,":memory:","","")
If DatabaseQuery(h2,"select sqlite_version();")
  If NextDatabaseRow(h2)
    Debug GetDatabaseString(h2,0)
  EndIf
  FinishDatabaseQuery(h2)
EndIf
UseSQLiteDatabase()
h1=OpenDatabase(-1,":memory:","","")
If DatabaseQuery(h1,"select sqlite_version();")
  If NextDatabaseRow(h1)
    Debug GetDatabaseString(h1,0)
  EndIf
  FinishDatabaseQuery(h1)
EndIf

Result: Crash

Or more simply:

Code: Select all

UseSQLiteDatabase("c:\pbincludes\sqlite3.dll")
h2=OpenDatabase(-1,":memory:","","")
If DatabaseQuery(h2,"select sqlite_version();")
  If NextDatabaseRow(h2)
    Debug GetDatabaseString(h2,0)
  EndIf
  FinishDatabaseQuery(h2)
EndIf

UseSQLiteDatabase()

If DatabaseQuery(h2,"select sqlite_version();")
  If NextDatabaseRow(h2)
    Debug GetDatabaseString(h2,0)
  EndIf
  FinishDatabaseQuery(h2)
EndIf

Result: IMA

Would be nice if any of the "use...()" resulted in a corresponding subsystem() query...

Posted: **Tue May 21, 2024 7:50 pm**

I will take a closer look, a second call should do nothing.

Posted: **Tue May 21, 2024 8:06 pm**

Cyllceaux wrote: Tue May 21, 2024 6:18 pm In my case I want to activate features which is only needed if there is UseSQLiteDatabase() called. But most the time it is not necessary.

This is why I would like to use use..() appear as results of subsystem() or somethings similar.
While FAR from ideal..

Code: Select all

If OpenDatabase(0,":memory:","","",#PB_Database_SQLite)
  MessageRequester("test","Used")
Else
  MessageRequester("test","not Used")
EndIf

in the IDE w/debugger, it will error but 'continue' works as expected.
In a compiled exe or w/o debugger, it works as expected.

I've had the same sort of need for which image formats to save (jpg,png) based on if the use...() was issued.

Posted: **Tue May 21, 2024 8:06 pm**

Fred wrote: Tue May 21, 2024 7:50 pm I will take a closer look, a second call should do nothing.

Thank you!

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