Name
scalb, scalbf, scalbl - multiply floating-point number by integral power of radix (OBSOLETE)Library
Math library ( libm ", " -lm )Synopsis
#include <math.h> [[deprecated]] double scalb(double " x ", double exp );
[[deprecated]] float scalbf(float " x ", float exp );
[[deprecated]] long double scalbl(long double " x ", long double exp );
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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
Description
These functions multiply their first argument x by FLT_RADIX (probably 2) to the power ofexp, that is: x * FLT_RADIX ** exp
The definition of FLT_RADIX can be obtained by including <float.h>.
Return Value
On success, these functions return x * FLT_RADIX **exp. If x or exp is a NaN, a NaN is returned.
If x is positive infinity (negative infinity), and exp is not negative infinity, positive infinity (negative infinity) is returned.
If x is +0 (-0), and exp is not positive infinity, +0 (-0) is returned.
If x is zero, and exp is positive infinity, a domain error occurs, and a NaN is returned.
If x is an infinity, and exp 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.
Errors
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 exp is positive infinity, \ or x is positive infinity and exp 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.
Attributes
For an explanation of the terms used in this section, see attributes(7).| Interface | Attribute | Value |
| T} | Thread safety | MT-Safe |
Standards
None.History
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.