On 7/4/23 04:19, Hairy Pixels via fpc-pascal wrote:
I've been exploring the string types and I'm curious now, does the classic Pascal "ShortString" even make sense anymore on modern computers? I'm running tests and I can't seem to find a way in which AnsiString overall performs worse than ShortString. Are there any examples where AnsiString is worse? I think if you passed strings around lots that would trigger the ref counting and InterlockedExchange (I saw this in my own code before and it unnerved me) but that's been hard to test.
ShortString is mainly for compatibility with Turbo Pascal, not for performance, IMHO. Although the FPC compiler itself still uses ShortString for performance reasons (I think the main advantage is the avoidance of the implicit try..finally blocks, needed for ansistrings). It might be interesting to benchmark the compiler with AnsiStrings instead of ShortStrings and see if there's a performance difference. But even if there is, a compiler is an extreme example. For 99% of the programs, performance impact of AnsiString is not an issue. I put {$H+} in almost all my new programs. I'd say that in 99% of the legit use cases, ShortString is used and needed for compatibility with legacy code, not for performance. Switching legacy code to {$H+} doesn't always work and may need additional fixes. Old code does things like S[0] := x instead of SetLength(S, x), etc. It also does uglier things, like FillChar() or Move() directly to/from string memory, or saves ShortStrings to files, as a part of a record, etc.
Nikolay _______________________________________________ fpc-pascal maillist - fpc-pascal@lists.freepascal.org https://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
