How fast can you allocate a large block of memory in C++?

Re:How fast can you allocate a large block of memory in C++? by gurkendoktor on Thursday January 16, 2020 @03:33AM (#22062655)

Doesn't that break when std::free does not have the default C++ calling convention? I think `decltype(std::free)` would be easier to read anyway, but writing a deleter class that calls std::free in its operator() has the advantage that it will not use any memory in the unique_ptr thanks to the empty base class optimization.

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Re:How fast can you allocate a large block of memory in C++? by SamReidHughes on Thursday January 16, 2020 @03:37AM (#22062677)

I don't think that's possible, and in that case the std::function wouldn't work either.

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Re:How fast can you allocate a large block of memory in C++? by gurkendoktor on Thursday January 16, 2020 @09:09AM (#22064605)

I was thinking about calling conventions because std::free can use extern "C", but the function pointer declaration in C++ code points to an extern "C++" function, and the standard says these are two distinctive types. Are they guaranteed to be compatible - since they're only linkage specifiers, not calling conventions? I'm not sure.

std::function would still work in this case because pointers to C functions have a normal operator().

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Re:How fast can you allocate a large block of memory in C++? by SamReidHughes on Thursday January 16, 2020 @09:45AM (#22064942)

Oh, right, it would work. Anyway, it looks like compilers have a known bug and they’re supposed to treat the types as incompatible.

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