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%2Fmath%2Fldexp.html | 79 ----------------------------------- 1 file changed, 79 deletions(-) delete mode 100644 devdocs/c/numeric%2Fmath%2Fldexp.html (limited to 'devdocs/c/numeric%2Fmath%2Fldexp.html') diff --git a/devdocs/c/numeric%2Fmath%2Fldexp.html b/devdocs/c/numeric%2Fmath%2Fldexp.html deleted file mode 100644 index b2e09059..00000000 --- a/devdocs/c/numeric%2Fmath%2Fldexp.html +++ /dev/null @@ -1,79 +0,0 @@ -

ldexp, ldexpf, ldexpl

Defined in header <math.h> 
float       ldexpf( float arg, int exp );
-		 (1) (since C99) 
double      ldexp( double arg, int exp );
-		 (2) 
long double ldexpl( long double arg, int exp );
-		 (3) (since C99)
Defined in header <tgmath.h> 
#define ldexp( arg, exp )
-		 (4) (since C99)
-1-3) Multiplies a floating point value arg by the number 2 raised to the exp power.
-4) Type-generic macro: If arg has type long double, ldexpl is called. Otherwise, if arg has integer type or the type double, ldexp is called. Otherwise, ldexpf is called, respectively.

Parameters

- - -
arg - floating point value
exp - integer value

Return value

If no errors occur, arg multiplied by 2 to the power of exp (arg×2exp) is returned.

-

If a range error due to overflow occurs, ±HUGE_VAL, ±HUGE_VALF, or ±HUGE_VALL is returned.

-

If a range error due to underflow occurs, the correct result (after rounding) is returned.

-

Error handling

Errors are reported as specified in math_errhandling.

-

If the implementation supports IEEE floating-point arithmetic (IEC 60559),

-

Notes

On binary systems (where FLT_RADIX is 2), ldexp is equivalent to scalbn.

-

The function ldexp ("load exponent"), together with its dual, frexp, can be used to manipulate the representation of a floating-point number without direct bit manipulations.

-

On many implementations, ldexp is less efficient than multiplication or division by a power of two using arithmetic operators.

-

Example

#include <stdio.h>
-#include <math.h>
-#include <float.h>
-#include <errno.h>
-#include <fenv.h>
-#pragma STDC FENV_ACCESS ON
-int main(void)
-{
-    printf("ldexp(7, -4) = %f\n", ldexp(7, -4));
-    printf("ldexp(1, -1074) = %g (minimum positive subnormal double)\n",
-            ldexp(1, -1074));
-    printf("ldexp(nextafter(1,0), 1024) = %g (largest finite double)\n",
-            ldexp(nextafter(1,0), 1024));
-    // special values
-    printf("ldexp(-0, 10) = %f\n", ldexp(-0.0, 10));
-    printf("ldexp(-Inf, -1) = %f\n", ldexp(-INFINITY, -1));
-    //error handling
-    errno = 0; feclearexcept(FE_ALL_EXCEPT);
-    printf("ldexp(1, 1024) = %f\n", ldexp(1, 1024));
-    if(errno == ERANGE) perror("    errno == ERANGE");
-    if(fetestexcept(FE_OVERFLOW)) puts("    FE_OVERFLOW raised");
-}

Possible output:

-
ldexp(7, -4) = 0.437500
-ldexp(1, -1074) = 4.94066e-324 (minimum positive subnormal double)
-ldexp(nextafter(1,0), 1024) = 1.79769e+308 (largest finite double)
-ldexp(-0, 10) = -0.000000
-ldexp(-Inf, -1) = -inf
-ldexp(1, 1024) = inf
-    errno == ERANGE: Numerical result out of range
-    FE_OVERFLOW raised

References

See also

- - -
-
(C99)(C99)
 breaks a number into significand and a power of 2
(function)
-
(C99)(C99)(C99)(C99)(C99)(C99)
 computes efficiently a number times FLT_RADIX raised to a power
(function)
C++ documentation for ldexp
-

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

-
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