Added/updated glibc feature test macro requirements

[thirdparty/man-pages.git] / man3 / scalb.3

.\" Copyright 2004 Andries Brouwer <aeb@cwi.nl>.
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.TH SCALB 3 2007-07-26 "" "Linux Programmer's Manual"
.SH NAME
scalb, scalbf, scalbl, scalbn, scalbnf, scalbnl, scalbln, scalblnf, scalblnl \-
multiply floating-point number by integral power of radix
.SH SYNOPSIS
.B #include <math.h>
.sp
.BI "double scalb(double " x ", double " exp );
.br
.BI "float scalbf(float " x ", double " exp );
.br
.BI "long double scalbl(long double " x ", double " exp );
.sp
.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 );
.sp
.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 );
.sp
Link with \fI-lm\fP.
.sp
.in -4n
Feature Test Macro Requirements for glibc (see
.BR feature_test_macros (7)):
.in
.sp
.ad l
.BR scalb (),
.BR scalbf (),
.BR scalbl ():
_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE\ >=\ 500
.br
.BR scalbn (),
.BR scalbnf (),
.BR scalbnl ():
_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE\ >=\ 600 || _ISOC99_SOURCE; or
.I cc\ -std=c99
.br
.BR scalbln (),
.BR scalblnf (),
.BR scalblnl ():
_XOPEN_SOURCE\ >=\ 600 || _ISOC99_SOURCE; or
.I cc\ -std=c99
.ad b
.SH DESCRIPTION
These functions multiply their first argument
.I x
by
.B FLT_RADIX
(probably 2) to the power
.IR exp .

If
.B FLT_RADIX
equals 2, then
.BR scalbn ()
is equivalent to
.BR ldexp (3).

The value of
.B FLT_RADIX
is found in
.IR <float.h> .
.\" not in /usr/include but in a gcc lib
.SH "CONFORMING TO"
The
.BR scalb ()
function is from 4.3BSD.
The
.BR scalbn ()
and
.BR scalbln ()
functions are from C99.
All three are in POSIX.1-2001.
The
.BR scalb ()
function is marked obsolescent.
.SH "SEE ALSO"
.BR ldexp (3)