https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94981
--- Comment #8 from Tony Reix <tony.reix at atos dot net> --- On fedora31/x86_64, when compiling with -funsigned-char, some parts of Boost math do not compile. With some changes like: static_cast<T>(-5) , it is easy to make these tests to work both with -fsigned-char or -funsigned-char. However, there are several other places where Boost expects chars to be signed and that would require to change them too. Moreover, I have no idea yet if such a change does modify the semantic of this Boost math code, or not. Moreover, Boost makes use of C++ include files which have a different behavior on AIX when converting floating point numbers to unsigned ints, vs Fedora. Thus, I should discuss with Boost community and check if Boost is designed to handle unsigned chars in addition to signed char, but some cases were not correctly handled, or if Boost requires signed chars.
