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| .TH SCALBLN 3 2017-09-15 "" "Linux Programmer's Manual" |
| .SH NAME |
| scalbn, scalbnf, scalbnl, scalbln, scalblnf, scalblnl \- |
| multiply floating-point number by integral power of radix |
| .SH SYNOPSIS |
| .B #include <math.h> |
| .PP |
| .BI "double scalbln(double " x ", long int " exp ); |
| .br |
| .BI "float scalblnf(float " x ", long int " exp ); |
| .br |
| .BI "long double scalblnl(long double " x ", long int " exp ); |
| .PP |
| .BI "double scalbn(double " x ", int " exp ); |
| .br |
| .BI "float scalbnf(float " x ", int " exp ); |
| .br |
| .BI "long double scalbnl(long double " x ", int " 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 scalbln (), |
| .BR scalblnf (), |
| .BR scalblnl (): |
| .RS |
| _ISOC99_SOURCE || _POSIX_C_SOURCE\ >=\ 200112L |
| || /* Since glibc 2.19: */ _DEFAULT_SOURCE |
| .RE |
| .br |
| .BR scalbn (), |
| .BR scalbnf (), |
| .BR scalbnl (): |
| .RS |
| _ISOC99_SOURCE || _POSIX_C_SOURCE\ >=\ 200112L |
| || /* 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 |
| is a NaN, a NaN is returned. |
| .PP |
| If |
| .I x |
| is positive infinity (negative infinity), |
| positive infinity (negative infinity) is returned. |
| .PP |
| If |
| .I x |
| is +0 (\-0), +0 (\-0) 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 |
| 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 |
| .SH VERSIONS |
| These functions first appeared in glibc in version 2.1. |
| .SH ATTRIBUTES |
| For an explanation of the terms used in this section, see |
| .BR attributes (7). |
| .TS |
| allbox; |
| lbw33 lb lb |
| l l l. |
| Interface Attribute Value |
| T{ |
| .BR scalbn (), |
| .BR scalbnf (), |
| .BR scalbnl (), |
| .br |
| .BR scalbln (), |
| .BR scalblnf (), |
| .BR scalblnl () |
| T} Thread safety MT-Safe |
| .TE |
| .SH CONFORMING TO |
| C99, POSIX.1-2001, POSIX.1-2008. |
| .SH NOTES |
| These functions differ from the obsolete functions described in |
| .BR scalb (3) |
| in the type of their second argument. |
| The functions described on this page have a second argument |
| of an integral type, while those in |
| .BR scalb (3) |
| have a second argument of type |
| .IR double . |
| .PP |
| If |
| .B FLT_RADIX |
| equals 2 (which is usual), then |
| .BR scalbn () |
| is equivalent to |
| .BR ldexp (3). |
| .SH SEE ALSO |
| .BR ldexp (3), |
| .BR scalb (3) |