ldexp(3) - NetBSD Manual Pages

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LDEXP(3)                NetBSD Library Functions Manual               LDEXP(3)


NAME

     ldexp, ldexpf -- multiply floating-point number by integral power of 2


LIBRARY

     Math Library (libm, -lm)


SYNOPSIS

     #include <math.h>

     double
     ldexp(double x, int exp);

     float
     ldexpf(float x, int exp);


DESCRIPTION

     The ldexp() family of functions compute

           x * 2^exp

     for a real floating-point number x.


RETURN VALUES

     The functions return the value of x times 2 raised to the power exp.
     Otherwise the following may occur:

           1.   If x is NaN, a NaN is returned.

           2.   If exp is zero or x is either ± 0 or ±oo, x is returned.

           3.   If the call would cause an overflow, a range error occurs and
                either ±HUGE_VAL, ±HUGE_VALF, or ±HUGE_VALL is returned,
                depending on the sign of x and the type of the return value.

           4.   If an underflow would be caused by the correct value, and the
                value is not representable, either 0.0 or an implementation-
                defined value is returned.


SEE ALSO

     frexp(3), math(3), modf(3)


STANDARDS

     The described functions conform to ISO/IEC 9899:1999 (``ISO C99'').

NetBSD 6.0                    September 18, 2011                    NetBSD 6.0