PROLOG

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

NAME

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

SYNOPSIS

       #include <math.h>

       double frexp(double num, int *exp);
       float frexpf(float num, int *exp);
       long double frexpl(long double num, int *exp);

DESCRIPTION

       The functionality described on this reference page is aligned with the ISO C standard. Any
       conflict between the requirements described here and the ISO C standard is  unintentional.
       This volume of POSIX.1‐2008 defers to the ISO C standard.

       These  functions shall break a floating-point number num into a normalized fraction and an
       integral power of 2. The integer exponent shall be stored in the int object pointed to  by
       exp.

RETURN VALUE

       For  finite  arguments,  these  functions  shall  return  the  value  x, such that x has a
       magnitude in the interval [½,1) or 0, and num equals x times 2 raised to the power *exp.

       If num is NaN, a NaN shall be returned, and the value of *exp is unspecified.

       If num is ±0, ±0 shall be returned, and the value of *exp shall be 0.

       If num is ±Inf, num shall be returned, and the value of *exp is unspecified.

ERRORS

       No errors are defined.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       None.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       isnan(), ldexp(), modf()

       The Base Definitions volume of POSIX.1‐2008, <math.h>

COPYRIGHT

       Portions of this text are reprinted and  reproduced  in  electronic  form  from  IEEE  Std
       1003.1,  2013  Edition,  Standard  for Information Technology -- Portable Operating System
       Interface (POSIX), The Open Group Base Specifications Issue 7, Copyright (C) 2013  by  the
       Institute  of  Electrical  and  Electronics  Engineers,  Inc and The Open Group.  (This is
       POSIX.1-2008 with the  2013  Technical  Corrigendum  1  applied.)  In  the  event  of  any
       discrepancy  between  this  version and the original IEEE and The Open Group Standard, the
       original IEEE and The Open Group Standard is the referee document. The  original  Standard
       can be obtained online at http://www.unix.org/online.html .

       Any  typographical  or  formatting errors that appear in this page are most likely to have
       been introduced during the conversion of the source files to man page  format.  To  report
       such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .