Re: std::string allocator

["Stefan Olsson" <stefan at garcio dot com>]

Hi Paolo,

well, it doesn't seem that way - or else I'm doing something really wrong/wierd. I did the _very_ ugly test of adding a printf( "%d ", __n * sizeof(_Tp)) in the allocate (line 660 something) method of mt_alloc and it doesn't show up on strings - it does report usage on all other types (vectors, lists etc...).

I.e. compiling this little app will not generate any calls visible by the printf:
#include <string>

int main() {
  std::string foo = "this is a test";

  return 0;
}

Brgds
----- Original Message -----
Paolo Carlini wrote:
> Stefan Olsson wrote:
>
> >Hi folks,
> >
> >back with a new allocator related issue. Downloaded 4.1.0 and compiled with:
> >--enable-shared --enable-threads=posix --disable-checking --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --host=i386-redhat-linux --enable-libstdcxx-allocator=mt --enable-languages=c,c++
> >
> >This way I can enjoy the performance of mt_alloc without having to specify it every time (or rather set up a global define for each type). Not quite though...
> >...the std::string is defined in bits/stringfwd.h as:
> >typedef basic_string<char>    string;
> >
> >
> Then string uses std::allocator<_CharT>, and since you passed
> --enable-libstdcxx-allocator=mt at build time, the implementation of
> std::allocator *is* mt_allocator:
>
>   template<typename _Tp>
>     class allocator: public __glibcxx_base_allocator<_Tp>
>     ...
>
> I don't understand...
>
> Paolo.
>


Stefan Olsson
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