https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109818
--- Comment #15 from Jonathan Wakely <redi at gcc dot gnu.org> --- The reason that std::trunc is not provided is because (In reply to Jonathan Wakely from comment #11) > The problem is more likely to be that this macro is not defined for djgpp: > > #ifdef _GLIBCXX_USE_C99_MATH_TR1 > > And if djgpp doesn't have a full C99 math library then that would explain > why you don't have std::trunc (or any of the other C99 math functions). I've confirmed this is the problem. The configure test that defines that macro fails because these are missing: config.cc7:9: error: 'double_t' does not name a type; did you mean 'double'? config.cc8:27: error: 'float_t' does not name a type; did you mean 'float'? config.cc1:19: error: 'acoshl' was not declared in this scope; did you mean 'acoshf'? config.cc4:19: error: 'asinhl' was not declared in this scope; did you mean 'asinhf'? config.cc7:19: error: 'atanhl' was not declared in this scope; did you mean 'atanhf'? config.cc0:19: error: 'cbrtl' was not declared in this scope; did you mean 'cbrtf'? config.cc3:19: error: 'copysignl' was not declared in this scope; did you mean 'copysignf'? config.cc6:19: error: 'erfl' was not declared in this scope; did you mean 'erff'? config.cc9:19: error: 'erfcl' was not declared in this scope; did you mean 'erfcf'? config.cc1:19: error: 'exp2f' was not declared in this scope; did you mean 'expf'? config.cc2:19: error: 'exp2l' was not declared in this scope; did you mean 'exp2'? config.cc5:19: error: 'expm1l' was not declared in this scope; did you mean 'expm1f'? config.cc6:19: error: 'fdim' was not declared in this scope config.cc7:19: error: 'fdimf' was not declared in this scope config.cc8:19: error: 'fdiml' was not declared in this scope config.cc9:19: error: 'fma' was not declared in this scope config.cc0:19: error: 'fmaf' was not declared in this scope config.cc1:19: error: 'fmal' was not declared in this scope config.cc2:19: error: 'fmax' was not declared in this scope config.cc3:19: error: 'fmaxf' was not declared in this scope config.cc4:19: error: 'fmaxl' was not declared in this scope config.cc5:19: error: 'fmin' was not declared in this scope config.cc6:19: error: 'fminf' was not declared in this scope config.cc7:19: error: 'fminl' was not declared in this scope config.cc0:19: error: 'hypotl' was not declared in this scope; did you mean 'hypotf'? config.cc3:19: error: 'ilogbl' was not declared in this scope; did you mean 'ilogbf'? config.cc6:19: error: 'lgammal' was not declared in this scope; did you mean 'lgammaf'? config.cc7:19: error: 'log1pl' was not declared in this scope; did you mean 'log1pf'? config.cc0:19: error: 'log2l' was not declared in this scope; did you mean 'log2f'? config.cc3:19: error: 'logbl' was not declared in this scope; did you mean 'logbf'? config.cc3:19: error: 'nearbyint' was not declared in this scope config.cc4:19: error: 'nearbyintf' was not declared in this scope config.cc5:19: error: 'nearbyintl' was not declared in this scope config.cc8:19: error: 'nextafterl' was not declared in this scope; did you mean 'nextafterf'? config.cc9:19: error: 'nexttoward' was not declared in this scope config.cc0:19: error: 'nexttowardf' was not declared in this scope config.cc1:19: error: 'nexttowardl' was not declared in this scope config.cc4:19: error: 'remainderl' was not declared in this scope; did you mean 'remainderf'? config.cc5:19: error: 'remquo' was not declared in this scope config.cc6:19: error: 'remquof' was not declared in this scope config.cc7:19: error: 'remquol' was not declared in this scope config.cc4:19: error: 'scalbln' was not declared in this scope; did you mean 'scalbn'? config.cc5:19: error: 'scalblnf' was not declared in this scope; did you mean 'scalbnf'? config.cc6:19: error: 'scalblnl' was not declared in this scope; did you mean 'scalbnf'? config.cc9:19: error: 'scalbnl' was not declared in this scope; did you mean 'scalbnf'? config.cc0:19: error: 'tgamma' was not declared in this scope; did you mean 'lgamma'? config.cc1:19: error: 'tgammaf' was not declared in this scope; did you mean 'lgammaf'? config.cc2:19: error: 'tgammal' was not declared in this scope; did you mean 'lgammaf'? A proper fix would be to split up the configure test for USE_C99_MATH_TR1 to be more fine-grained, so that we use the subset of functions that are supported, instead of all or nothing.
