| .\" Copyright 2004 Andries Brouwer <aeb@cwi.nl>. |
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| .TH SCALB 3 2017-09-15 "" "Linux Programmer's Manual" |
| .SH NAME |
| scalb, scalbf, scalbl \- multiply floating-point number |
| by integral power of radix (OBSOLETE) |
| .SH SYNOPSIS |
| .B #include <math.h> |
| .PP |
| .BI "double scalb(double " x ", double " exp ); |
| .br |
| .BI "float scalbf(float " x ", float " exp ); |
| .br |
| .BI "long double scalbl(long double " x ", long double " exp ); |
| .PP |
| Link with \fI\-lm\fP. |
| .PP |
| .in -4n |
| Feature Test Macro Requirements for glibc (see |
| .BR feature_test_macros (7)): |
| .in |
| .PP |
| .ad l |
| .BR scalb (): |
| .RS 4 |
| _XOPEN_SOURCE\ >=\ 500 |
| .\" || _XOPEN_SOURCE\ &&\ _XOPEN_SOURCE_EXTENDED |
| || /* Since glibc 2.19: */ _DEFAULT_SOURCE |
| || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE |
| .RE |
| .br |
| .BR scalbf (), |
| .BR scalbl (): |
| .RS 4 |
| _XOPEN_SOURCE\ >=\ 600 |
| || /* Since glibc 2.19: */ _DEFAULT_SOURCE |
| || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE |
| .RE |
| .ad b |
| .SH DESCRIPTION |
| These functions multiply their first argument |
| .I x |
| by |
| .B FLT_RADIX |
| (probably 2) |
| to the power of |
| .IR exp , |
| that is: |
| .PP |
| .nf |
| x * FLT_RADIX ** exp |
| .fi |
| .PP |
| The definition of |
| .B FLT_RADIX |
| can be obtained by including |
| .IR <float.h> . |
| .\" not in /usr/include but in a gcc lib |
| .SH RETURN VALUE |
| On success, these functions return |
| .IR x |
| * |
| .B FLT_RADIX |
| ** |
| .IR exp . |
| .PP |
| If |
| .I x |
| or |
| .I exp |
| is a NaN, a NaN is returned. |
| .PP |
| If |
| .I x |
| is positive infinity (negative infinity), |
| and |
| .I exp |
| is not negative infinity, |
| positive infinity (negative infinity) is returned. |
| .PP |
| If |
| .I x |
| is +0 (\-0), and |
| .I exp |
| is not positive infinity, +0 (\-0) is returned. |
| .PP |
| If |
| .I x |
| is zero, and |
| .I exp |
| is positive infinity, |
| a domain error occurs, and |
| a NaN is returned. |
| .PP |
| If |
| .I x |
| is an infinity, |
| and |
| .I exp |
| is negative infinity, |
| a domain error occurs, and |
| a NaN is returned. |
| .PP |
| If the result overflows, |
| a range error occurs, |
| and the functions return |
| .BR HUGE_VAL , |
| .BR HUGE_VALF , |
| or |
| .BR HUGE_VALL , |
| respectively, with a sign the same as |
| .IR x . |
| .PP |
| If the result underflows, |
| a range error occurs, |
| and the functions return zero, with a sign the same as |
| .IR x . |
| .SH ERRORS |
| See |
| .BR math_error (7) |
| for information on how to determine whether an error has occurred |
| when calling these functions. |
| .PP |
| The following errors can occur: |
| .TP |
| Domain error: \fIx\fP is 0, and \fIexp\fP is positive infinity, \ |
| or \fIx\fP is positive infinity and \fIexp\fP is negative infinity \ |
| and the other argument is not a NaN |
| .\" .I errno |
| .\" is set to |
| .\" .BR EDOM . |
| An invalid floating-point exception |
| .RB ( FE_INVALID ) |
| is raised. |
| .TP |
| Range error, overflow |
| .\" .I errno |
| .\" is set to |
| .\" .BR ERANGE . |
| An overflow floating-point exception |
| .RB ( FE_OVERFLOW ) |
| is raised. |
| .TP |
| Range error, underflow |
| .\" .I errno |
| .\" is set to |
| .\" .BR ERANGE . |
| An underflow floating-point exception |
| .RB ( FE_UNDERFLOW ) |
| is raised. |
| .PP |
| These functions do not set |
| .IR errno . |
| .\" FIXME . Is it intentional that these functions do not set errno? |
| .\" Bug raised: http://sources.redhat.com/bugzilla/show_bug.cgi?id=6803 |
| .\" Bug raised: http://sources.redhat.com/bugzilla/show_bug.cgi?id=6804 |
| .SH ATTRIBUTES |
| For an explanation of the terms used in this section, see |
| .BR attributes (7). |
| .TS |
| allbox; |
| lbw28 lb lb |
| l l l. |
| Interface Attribute Value |
| T{ |
| .BR scalb (), |
| .BR scalbf (), |
| .BR scalbl () |
| T} Thread safety MT-Safe |
| .TE |
| .SH CONFORMING TO |
| .BR scalb () |
| is specified in POSIX.1-2001, but marked obsolescent. |
| POSIX.1-2008 removes the specification of |
| .BR scalb (), |
| recommending the use of |
| .BR scalbln (3), |
| .BR scalblnf (3), |
| or |
| .BR scalblnl (3) |
| instead. |
| The |
| .BR scalb () |
| function is from 4.3BSD. |
| .PP |
| .BR scalbf () |
| and |
| .BR scalbl () |
| are unstandardized; |
| .BR scalbf () |
| is nevertheless present on several other systems |
| .\" Looking at header files: scalbf() is present on the |
| .\" BSDs, Tru64, HP-UX 11, Irix 6.5; scalbl() is on HP-UX 11 and Tru64. |
| .SH SEE ALSO |
| .BR ldexp (3), |
| .BR scalbln (3) |