scalb, scalbf, scalbl

Math library (libm, -lm)

#include <math.h>

[[deprecated]] double scalb(double x, double e);
[[deprecated]] float scalbf(float x, float e);
[[deprecated]] long double scalbl(long double x, long double e);

scalb():

    _XOPEN_SOURCE >= 500
        || /* Since glibc 2.19: */ _DEFAULT_SOURCE
        || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

scalbf(), scalbl():

    _XOPEN_SOURCE >= 600
        || /* Since glibc 2.19: */ _DEFAULT_SOURCE
        || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

These functions multiply their first argument x by FLT_RADIX (probably 2) to the power of e, that is:

    x * FLT_RADIX ** e

The definition of FLT_RADIX can be obtained by including <float.h>.

On success, these functions return x * FLT_RADIX ** e.

If x or e is a NaN, a NaN is returned.

If x is positive infinity (negative infinity), and e is not negative infinity, positive infinity (negative infinity) is returned.

If x is +0 (-0), and e is not positive infinity, +0 (-0) is returned.

If x is zero, and e is positive infinity, a domain error occurs, and a NaN is returned.

If x is an infinity, and e is negative infinity, a domain error occurs, and a NaN is returned.

If the result overflows, a range error occurs, and the functions return HUGE_VAL, HUGE_VALF, or HUGE_VALL, respectively, with a sign the same as x.

If the result underflows, a range error occurs, and the functions return zero, with a sign the same as x.

See math_error(7) for information on how to determine whether an error has occurred when calling these functions.

The following errors can occur:

Domain error: x is 0, and e is positive infinity, or x is positive infinity and e is negative infinity and the other argument is not a NaN

errno is set to EDOM. An invalid floating-point exception (FE_INVALID) is raised.

Range error, overflow

errno is set to ERANGE. An overflow floating-point exception (FE_OVERFLOW) is raised.

Range error, underflow

errno is set to ERANGE. An underflow floating-point exception (FE_UNDERFLOW) is raised.

For an explanation of the terms used in this section, see attributes(7).

None.

scalb()

4.3BSD. Obsolescent in POSIX.1-2001; Removed in POSIX.1-2008, recommending the use of scalbln(3), scalblnf(3), or scalblnl(3) instead.

Before glibc 2.20, these functions did not set errno for domain and range errors.

ldexp(3), scalbln(3)