1FREXP(3P)                  POSIX Programmer's Manual                 FREXP(3P)
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PROLOG

6       This  manual  page is part of the POSIX Programmer's Manual.  The Linux
7       implementation of this interface may differ (consult the  corresponding
8       Linux  manual page for details of Linux behavior), or the interface may
9       not be implemented on Linux.
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11

NAME

13       frexp, frexpf, frexpl — extract mantissa and  exponent  from  a  double
14       precision number
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SYNOPSIS

17       #include <math.h>
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19       double frexp(double num, int *exp);
20       float frexpf(float num, int *exp);
21       long double frexpl(long double num, int *exp);
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DESCRIPTION

24       The  functionality described on this reference page is aligned with the
25       ISO C standard. Any conflict between the  requirements  described  here
26       and  the  ISO C  standard is unintentional. This volume of POSIX.1‐2008
27       defers to the ISO C standard.
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29       These functions shall break a floating-point number num into a  normal‐
30       ized fraction and an integral power of 2. The integer exponent shall be
31       stored in the int object pointed to by exp.
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RETURN VALUE

34       For finite arguments, these functions shall return the  value  x,  such
35       that  x  has  a  magnitude in the interval [½,1) or 0, and num equals x
36       times 2 raised to the power *exp.
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38       If num is NaN, a NaN shall be  returned,  and  the  value  of  *exp  is
39       unspecified.
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41       If num is ±0, ±0 shall be returned, and the value of *exp shall be 0.
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43       If num is ±Inf, num shall be returned, and the value of *exp is unspec‐
44       ified.
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ERRORS

47       No errors are defined.
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49       The following sections are informative.
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EXAMPLES

52       None.
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APPLICATION USAGE

55       None.
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RATIONALE

58       None.
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FUTURE DIRECTIONS

61       None.
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SEE ALSO

64       isnan(), ldexp(), modf()
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66       The Base Definitions volume of POSIX.1‐2008, <math.h>
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69       Portions of this text are reprinted and reproduced in  electronic  form
70       from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
71       -- Portable Operating System Interface (POSIX),  The  Open  Group  Base
72       Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
73       cal and Electronics Engineers,  Inc  and  The  Open  Group.   (This  is
74       POSIX.1-2008  with  the  2013  Technical Corrigendum 1 applied.) In the
75       event of any discrepancy between this version and the original IEEE and
76       The  Open Group Standard, the original IEEE and The Open Group Standard
77       is the referee document. The original Standard can be  obtained  online
78       at http://www.unix.org/online.html .
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80       Any  typographical  or  formatting  errors that appear in this page are
81       most likely to have been introduced during the conversion of the source
82       files  to  man page format. To report such errors, see https://www.ker‐
83       nel.org/doc/man-pages/reporting_bugs.html .
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87IEEE/The Open Group                  2013                            FREXP(3P)
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