1FREXP(3P) POSIX Programmer's Manual FREXP(3P)
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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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12 frexp, frexpf, frexpl - extract mantissa and exponent from a double
13 precision number
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16 #include <math.h>
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18 double frexp(double num, int *exp);
19 float frexpf(float num, int *exp);
20 long double frexpl(long double num, int *exp);
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24 These functions shall break a floating-point number num into a normal‐
25 ized fraction and an integral power of 2. The integer exponent shall be
26 stored in the int object pointed to by exp.
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29 For finite arguments, these functions shall return the value x, such
30 that x has a magnitude in the interval [0.5,1) or 0, and num equals x
31 times 2 raised to the power *exp.
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33 If num is NaN, a NaN shall be returned, and the value of *exp is
34 unspecified.
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36 If num is ±0, ±0 shall be returned, and the value of *exp shall be 0.
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38 If num is ±Inf, num shall be returned, and the value of *exp is unspec‐
39 ified.
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42 No errors are defined.
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44 The following sections are informative.
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47 None.
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50 None.
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59 isnan(), ldexp(), modf(), the Base Definitions volume of
60 IEEE Std 1003.1-2001, <math.h>
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63 Portions of this text are reprinted and reproduced in electronic form
64 from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
65 -- Portable Operating System Interface (POSIX), The Open Group Base
66 Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
67 Electrical and Electronics Engineers, Inc and The Open Group. In the
68 event of any discrepancy between this version and the original IEEE and
69 The Open Group Standard, the original IEEE and The Open Group Standard
70 is the referee document. The original Standard can be obtained online
71 at http://www.opengroup.org/unix/online.html .
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75IEEE/The Open Group 2003 FREXP(3P)