[fpc-pascal] Reproducible code: DLL calling Firebird crashes

Michael Van Canneyt michael at freepascal.org
Tue Sep 30 13:19:10 CEST 2014

On Tue, 30 Sep 2014, Mark Morgan Lloyd wrote:

> Reinier Olislagers wrote:
>> On 29/09/2014 19:30, Reinier Olislagers wrote:
>>> Re bug report: agreed. I'll raise it.
> Jonas has already closed it, noting
> "http://msdn.microsoft.com/en-us/library/windows/desktop/ms682583%28v=vs.85%29.aspx
> "***
> The entry-point function should perform only simple initialization or 
> termination tasks. It must not call the LoadLibrary or LoadLibraryEx function 
> (or a function that calls these functions), because this may create 
> dependency loops in the DLL load order. This can result in a DLL being used 
> before the system has executed its initialization code.
> ***
> "I.e., what you are doing is unsupported ("must not call the LoadLibrary or 
> LoadLibraryEx function"). I think that on most unix platforms, trying to load 
> libraries from other the init function of other libraries is not supported 
> either."
> However I'd precede that by a thought based on what Jose said. In your 
> example, you're opening the database in the initialisation block of 
> businesslayer.pas, which is invoked at an arbitrary position in the init 
> sequence of the DLL/so. If that operation were moved instead to the 
> initialisation block of testdbdll.lpr, which in the context of the DLL/so is 
> analogous to a program's main block, it might work.

No. this is not correct. For a library, this is analogous to initialization code of a unit, it's just the 'last' unit being initialized.


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