Even though the rounding direction macros might expand to constants corresponding to the values of FLT_ROUNDS, they are not required to do so. For example: #include .h> void f (double x) { #pragma STDC FENV_ACCESS ON void g (double) void h (double) /* … */ g (x + 1) h (x + 1) .
For example : #include fenv.h > void f(double x) { #pragma STDC FENV_ACCESS ON void g(double) void h(double) /* … */ g(x + 1) h(x + 1) /* …
For example: #include void f(double x) { #pragma STDC FENV_ACCESS ON void g(double) void h(double) /* … */ g(x + 1) h(x + 1) /* …
Provided by: manpages-posix-dev_2.16-1_all NAME fenv.h – floating-point environment SYNOPSIS #include fenv.h > DESCRIPTION The fenv.h > header shall define the following data types through typedef: fenv_t Represents the entire floating-point environment. The floating-point environment refers collectively to any floating-point status flags and control modes supported by the implementation.
The fenv.h > header shall define the following macro, which represents the default floating-point environment (that is, the one installed at program startup) and has type pointer to const-qualified fenv_t. It can be used as an argument to the functions within the fenv.h.
The header fenv.h >declares two types and several macros and functions toprovide access to the floating-point environment. The floating-pointenvironment refers collectively to any floating-point status flags and controlmodes supported by the implementation. 1A floating-point status flag is asystem variable whose value is set (but never cleared) …
These functions can be used to control a variety of settings that affect floating-point computations, for example, the rounding mode, on what conditions exceptions occur, when numbers are flushed to zero, etc. The floating-point environment functions and types are defined in.
Example: The below example shows the usage of FE_TONEAREST macro. #include #include #include #pragma STDC FENV_ACCESS ON int main () { //to-nearest rounding direction mode fesetround(FE_TONEAREST) printf(rint (10.2) = %.1fn, rint(10.2)) printf(rint (10.8) = %.1fn, rint(10.8)) printf(rint (-5.2) = %.1fn, …
Certain library implementations may define additional macro constants in to identify additional floating-point exceptions (with their corresponding macros also beginning with FE_). See math_errhandling for more details. Example: The below example shows the usage of FE_ALL_EXCEPT macro.
C – feholdexcept() Function The C fenv.h > feholdexcept() function attempts to store the current state of the floating-point environment into the fenv_t object pointed by envp. Programs calling this function shall ensure that pragma FENV_ACCESS is enabled for the call.
