On 02.04.2017 11:22, Ryan Joseph wrote: > >> On Apr 1, 2017, at 9:25 PM, Jürgen Hestermann <juergen.hesterm...@gmx.de> >> wrote: >> >> If you just need to reuse the same array and only need to zero its elements >> then of course fillchar would be the fastest approach (it saves the memory >> reallocation step). > > Why is this “of course”? What’s the implementation of FillChar exactly? For > all I know it has to iterate over a range of bytes and this could be slower > than allocation of memory. Maybe some of the compiler people know these > details.
The question is not about the implementation of FillChar. It's about reallocating a dynamic array as to reallocate it you'd need to do === code begin === SetLength(arr, 0); SetLength(arr, newlen); === code end === And that this is more complex than === code begin === FillChar(arr, SizeOf(arr[0]) * Length(arr), 0); === code end === can be easily seen by looking at the implementation of SetLength() in $fpcdir/rtl/inc/dynarr.inc, fpc_dynarray_setlength(). Especially since line 220 (at least in the current revision) contains a call to FillChar(), the whole ordeal can only be *more* complex than FillChar(). Regards, Sven _______________________________________________ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
