search

boostorg / core

Boost Core Utilities
133 stars 83 forks source link

New cmath.hpp does not work with pre C++11/C99 compilers #96

Closed yachoor closed 3 years ago

yachoor commented 3 years ago

I'm using ARMCC 4.1 with hardware vendor provided standard C++ library. My math.h and cmath headers do not have isfinite, isnan, isinf, etc. functions - they were not in standard before C++11/C99 The change of dependency in lexical_cast from Boost.Math to core/cmath.hpp in boost 1.76 breaks project compilation as reported in https://github.com/boostorg/lexical_cast/issues/49

pdimov commented 3 years ago

It's hard to find information on ARMCC 4.1. Does it support infinities and NaN at all? It seems that ARMCC 5 has isinf and isnan in <math.h> as part of its C99 support, but I can find no documentation for 4.1, and I've no idea how to implement these functions there.

yachoor commented 3 years ago

The headers and standard library are not taken from compiler toolchain and don't have C99 support - they're provided by hardware vendor with their proprietary operating system. The generic implementation from Boost.Math (boost\math\special_functions\fpclassify.hpp) works fine with it. I think it uses the 3rd version:

  1. If the platform is not C99 compliant, and the binary format for a floating point type (float, double or long double) can not be determined at compile time, then comparison with std::numeric_limits values is used.
pdimov commented 3 years ago

Should be fixed now, after https://github.com/boostorg/core/commit/8043bafb6b02bb705961e6c3973746050a81c04a and https://github.com/boostorg/core/commit/177c093151c0b8a5b21d4b2e91cff2264dc69788.

yachoor commented 3 years ago

Thank you, this fixes the compilation for me