From 82ba818ff456bcd6d56a06226e3f27e98fbb55c3 Mon Sep 17 00:00:00 2001 From: Craig Jennings Date: Thu, 14 Aug 2025 22:58:58 -0500 Subject: removing all downloaded devdocs files --- devdocs/c/numeric%2Ffenv%2Ffeholdexcept.html | 74 ---------------------------- 1 file changed, 74 deletions(-) delete mode 100644 devdocs/c/numeric%2Ffenv%2Ffeholdexcept.html (limited to 'devdocs/c/numeric%2Ffenv%2Ffeholdexcept.html') diff --git a/devdocs/c/numeric%2Ffenv%2Ffeholdexcept.html b/devdocs/c/numeric%2Ffenv%2Ffeholdexcept.html deleted file mode 100644 index bb870968..00000000 --- a/devdocs/c/numeric%2Ffenv%2Ffeholdexcept.html +++ /dev/null @@ -1,74 +0,0 @@ -

feholdexcept

Defined in header <fenv.h> 
int feholdexcept( fenv_t* envp );
-		 (since C99)

First, saves the current floating-point environment to the object pointed to by envp (similar to fegetenv), then clears all floating-point status flags, and then installs the non-stop mode: future floating-point exceptions will not interrupt execution (will not trap), until the floating-point environment is restored by feupdateenv or fesetenv.

-

This function may be used in the beginning of a subroutine that must hide the floating-point exceptions it may raise from the caller. If only some exceptions must be suppressed, while others must be reported, the non-stop mode is usually ended with a call to feupdateenv after clearing the unwanted exceptions.

-

Parameters

- -
envp - pointer to the object of type fenv_t where the floating-point environment will be stored

Return value

​0​ on success, non-zero otherwise.

-

Example

#include <stdio.h>
-#include <fenv.h>
-#include <float.h>
- 
-#pragma STDC FENV_ACCESS ON
- 
-void show_fe_exceptions(void)
-{
-    printf("current exceptions raised: ");
-    if(fetestexcept(FE_DIVBYZERO))     printf(" FE_DIVBYZERO");
-    if(fetestexcept(FE_INEXACT))       printf(" FE_INEXACT");
-    if(fetestexcept(FE_INVALID))       printf(" FE_INVALID");
-    if(fetestexcept(FE_OVERFLOW))      printf(" FE_OVERFLOW");
-    if(fetestexcept(FE_UNDERFLOW))     printf(" FE_UNDERFLOW");
-    if(fetestexcept(FE_ALL_EXCEPT)==0) printf(" none");
-    printf("\n");
-}
- 
-double x2 (double x)   /* times two */
-{
-    fenv_t curr_excepts;
- 
-    /* Save and clear current f-p environment. */
-    feholdexcept(&curr_excepts);
- 
-    /* Raise inexact and overflow exceptions. */
-    printf("In x2():  x = %f\n", x=x*2.0);
-    show_fe_exceptions();
-    feclearexcept(FE_INEXACT);   /* hide inexact exception from caller */
- 
-    /* Merge caller's exceptions (FE_INVALID)        */
-    /* with remaining x2's exceptions (FE_OVERFLOW). */
-    feupdateenv(&curr_excepts);
-    return x;
-}
- 
-int main(void)
-{    
-    feclearexcept(FE_ALL_EXCEPT);
-    feraiseexcept(FE_INVALID);   /* some computation with invalid argument */
-    show_fe_exceptions();
-    printf("x2(DBL_MAX) = %f\n", x2(DBL_MAX));
-    show_fe_exceptions();
- 
-    return 0;
-}

Output:

-
current exceptions raised:  FE_INVALID
-In x2():  x = inf
-current exceptions raised:  FE_INEXACT FE_OVERFLOW
-x2(DBL_MAX) = inf
-current exceptions raised:  FE_INVALID FE_OVERFLOW

References

See also

- - - -
-
(C99)
 restores the floating-point environment and raises the previously raise exceptions
(function)
-
(C99)
 saves or restores the current floating-point environment
(function)
-
(C99)
 default floating-point environment
(macro constant)
C++ documentation for feholdexcept
-

- © cppreference.com
Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.
- https://en.cppreference.com/w/c/numeric/fenv/feholdexcept -

-
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