The Single UNIX ® Specification, Version 2
Copyright © 1997 The Open Group

 NAME

ldexp - load exponent of a floating point number

 SYNOPSIS



#include <math.h>

double ldexp(double x, int exp);

 DESCRIPTION

The ldexp() function computes the quantity x * 2exp.

An application wishing to check for error situations should set errno to 0 before calling ldexp(). If errno is non-zero on return, or the return value is NaN, an error has occurred.

 RETURN VALUE

Upon successful completion, ldexp() returns a double representing the value x multiplied by 2 raised to the power exp.

If the value of x is NaN, NaN is returned and errno may be set to [EDOM].

If ldexp() would cause overflow, ±HUGE_VAL is returned (according to the sign of x), and errno is set to [ERANGE].

If ldexp() would cause underflow, 0 is returned and errno may be set to [ERANGE].

 ERRORS

The ldexp() function will fail if:
[ERANGE]
The value to be returned would have caused overflow.

The ldexp() function may fail if:

[EDOM]
The argument x is NaN.
[ERANGE]
The value to be returned would have caused underflow.

No other errors will occur.

 EXAMPLES

None.

 APPLICATION USAGE

None.

 FUTURE DIRECTIONS

None.

 SEE ALSO

frexp(), isnan(), <math.h>.

DERIVATION

Derived from Issue 1 of the SVID.

UNIX ® is a registered Trademark of The Open Group.
Copyright © 1997 The Open Group
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