Thanks it's working now. The docs at https://www.freepascal.org/docs-html/rtl/system/tobject.newinstance.html confused me also. It says:
" If the memory was allocated, the class will be initialized by a call to InitInstance" The text "will be" is what confused me. This implies to me it will be done by Object somewhere higher up in the chain. It should read: "If memory was allocated it must be initialized by a call to InitInstance" > On Jun 4, 2024, at 7:06 PM, Sven Barth via fpc-pascal > <fpc-pascal@lists.freepascal.org> wrote: > > Hairy Pixels via fpc-pascal <fpc-pascal@lists.freepascal.org> schrieb am Di., > 4. Juni 2024, 10:54: > In the manual it at https://www.freepascal.org/docs-html/ref/refse38.html it > says "Calling the constructor will provoke a call to the virtual class method > NewInstance, which, in its default implementation, calls GetMem, to allocate > enough space to hold the class instance data, and then zeroes out the memory." > > I'm trying this like below but it crashes. Is this correct? The fact > NewInstance returns TObject instead of Pointer doesn't make sense to me and > suggests this isn't correct. > > class function TDataObject.NewInstance: TObject; > begin > result := TObject(GetMem(InstanceSize)); > end; > > You also need to call TObject.InitInstance() on the allocated memory (that > should probably be mentioned in the documentation...). > > Regards, > Sven > _______________________________________________ > fpc-pascal maillist - fpc-pascal@lists.freepascal.org > https://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal Regards, Ryan Joseph _______________________________________________ fpc-pascal maillist - fpc-pascal@lists.freepascal.org https://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
