Re: libpq++ and strings.
От | J. T. Vermeulen |
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Тема | Re: libpq++ and strings. |
Дата | |
Msg-id | 20010517145934.W14645@cistron.nl обсуждение исходный текст |
Ответ на | libpq++ and strings. (Carlos Moreno <moreno@mochima.com>) |
Список | pgsql-interfaces |
On Wed, 16 May 2001, Carlos Moreno wrote: > I wonder why all the string parameters and return values > are expressed in the form of char * or const char * ? Performance would be one reason, I'd say. const char * is easier to tune, and of course the underlying library uses const char *'s anyway. Also of course, a string is easily constructed from a const char * but the other way needs an explicit method call. OTOH I do think you have a point w.r.t. the obvious mistakes to make, and the lack of help from the compiler in spotting them. > Why not just changing all the parameters and return > values to `const string &' and/or `string' ? One possible tradeoff (and one I was leaning towards) is to take string parameters (so passing const char [] will still work) but return const char * in case you don't need the extras of a full C++ string. Unfortunately this doesn't help with the comparison-with-string-constant problem you cite. I guess this one boils down to how important performance is. One thing I'd like to do about it in the upcoming version is to provide type-safe access to the tuples. There'd still be a GetValue() returning const char *, but you wouldn't need to use it the way you showed in your example, because you'd be able to read it simply as a native bool. Jeroen
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