From 3d08cd331c1adcf0d917392f7e527b3f00511748 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Fri, 24 May 2024 06:52:22 +0200 Subject: Merging upstream version 6.8. Signed-off-by: Daniel Baumann --- man/man3/frexp.3 | 141 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 141 insertions(+) create mode 100644 man/man3/frexp.3 (limited to 'man/man3/frexp.3') diff --git a/man/man3/frexp.3 b/man/man3/frexp.3 new file mode 100644 index 0000000..3d357c9 --- /dev/null +++ b/man/man3/frexp.3 @@ -0,0 +1,141 @@ +'\" t +.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk) +.\" +.\" SPDX-License-Identifier: Linux-man-pages-copyleft +.\" +.\" References consulted: +.\" Linux libc source code +.\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991) +.\" 386BSD man pages +.\" Modified 1993-07-24 by Rik Faith (faith@cs.unc.edu) +.\" Modified 2002-07-27 by Walter Harms +.\" (walter.harms@informatik.uni-oldenburg.de) +.\" +.TH frexp 3 2024-05-02 "Linux man-pages (unreleased)" +.SH NAME +frexp, frexpf, frexpl \- convert floating-point number to fractional +and integral components +.SH LIBRARY +Math library +.RI ( libm ", " \-lm ) +.SH SYNOPSIS +.nf +.B #include +.P +.BI "double frexp(double " x ", int *" exp ); +.BI "float frexpf(float " x ", int *" exp ); +.BI "long double frexpl(long double " x ", int *" exp ); +.fi +.P +.RS -4 +Feature Test Macro Requirements for glibc (see +.BR feature_test_macros (7)): +.RE +.P +.BR frexpf (), +.BR frexpl (): +.nf + _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L + || /* Since glibc 2.19: */ _DEFAULT_SOURCE + || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE +.fi +.SH DESCRIPTION +These functions are used to split the number +.I x +into a +normalized fraction and an exponent which is stored in +.IR exp . +.SH RETURN VALUE +These functions return the normalized fraction. +If the argument +.I x +is not zero, +the normalized fraction is +.I x +times a power of two, +and its absolute value is always in the range 1/2 (inclusive) to +1 (exclusive), that is, [0.5,1). +.P +If +.I x +is zero, then the normalized fraction is +zero and zero is stored in +.IR exp . +.P +If +.I x +is a NaN, +a NaN is returned, and the value of +.I *exp +is unspecified. +.P +If +.I x +is positive infinity (negative infinity), +positive infinity (negative infinity) is returned, and the value of +.I *exp +is unspecified. +.SH ERRORS +No errors occur. +.SH ATTRIBUTES +For an explanation of the terms used in this section, see +.BR attributes (7). +.TS +allbox; +lbx lb lb +l l l. +Interface Attribute Value +T{ +.na +.nh +.BR frexp (), +.BR frexpf (), +.BR frexpl () +T} Thread safety MT-Safe +.TE +.SH STANDARDS +C11, POSIX.1-2008. +.SH HISTORY +C99, POSIX.1-2001. +.P +The variant returning +.I double +also conforms to +SVr4, 4.3BSD, C89. +.SH EXAMPLES +The program below produces results such as the following: +.P +.in +4n +.EX +.RB "$" " ./a.out 2560" +frexp(2560, &e) = 0.625: 0.625 * 2\[ha]12 = 2560 +.RB "$" " ./a.out \-4" +frexp(\-4, &e) = \-0.5: \-0.5 * 2\[ha]3 = \-4 +.EE +.in +.SS Program source +\& +.\" SRC BEGIN (frexp.c) +.EX +#include +#include +#include +#include +\& +int +main(int argc, char *argv[]) +{ + double x, r; + int exp; +\& + x = strtod(argv[1], NULL); + r = frexp(x, &exp); +\& + printf("frexp(%g, &e) = %g: %g * %d\[ha]%d = %g\en", x, r, r, 2, exp, x); + exit(EXIT_SUCCESS); +} +.EE +.\" SRC END +.SH SEE ALSO +.BR ldexp (3), +.BR modf (3) -- cgit v1.2.3