ldexp, _ldexpl

Description

Compute a real number from the mantissa and exponent.

#include <math.h>

double ldexp( double x, int exp );

long double _ldexpl( long double x, int exp );

Remarks

The ldexp and _ldexpl functions calculate the value of x * 2exp.

Return Value

The ldexp and _ldexpl functions return x * 2exp. If an overflow results, the functions return ±HUGE_VAL (depending on the sign of x) and set errno to ERANGE.

The _ldexpl function uses the 80-bit, 10-byte coprocessor form of arguments and return values. See the reference page on the long double functions for more details on this data type.

Compatibility

ldexp

Standards:ANSI, UNIX

16-Bit:DOS, QWIN, WIN, WIN DLL

32-Bit:DOS32X

_ldexpl

Standards:None

16-Bit:DOS, QWIN, WIN, WIN DLL

32-Bit:None

See Also

frexp, modf

Example

/* LDEXP.C */

#include <math.h>

#include <stdio.h>

void main( void )

{

double x = 4.0, y;

int p = 3;

y = ldexp( x, p );

printf( "%2.1f times two to the power of %d is %2.1f\n", x, p, y );

}

Output

4.0 times two to the power of 3 is 32.0