pow man page on Archlinux

Man page or keyword search:  
man Server   11224 pages
apropos Keyword Search (all sections)
Output format
Archlinux logo
[printable version]

POW(3P)			   POSIX Programmer's Manual		       POW(3P)

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
       pow, powf, powl — power function

SYNOPSIS
       #include <math.h>

       double pow(double x, double y);
       float powf(float x, float y);
       long double powl(long double x, long double y);

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 compute the value of x raised to the power y, xy.
       If x is negative, the application shall ensure that  y  is  an  integer
       value.

       An  application	wishing to check for error situations should set errno
       to zero and  call  feclearexcept(FE_ALL_EXCEPT)	before	calling	 these
       functions. On return, if errno is non-zero or fetestexcept(FE_INVALID |
       FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero,	an  error  has
       occurred.

RETURN VALUE
       Upon successful completion, these functions shall return the value of x
       raised to the power y.

       For finite values of x < 0, and	finite	non-integer  values  of	 y,  a
       domain  error  shall  occur  and either a NaN (if representable), or an
       implementation-defined value shall be returned.

       If the correct value would cause overflow, a range  error  shall	 occur
       and  pow(),  powf(), and powl() shall return ±HUGE_VAL, ±HUGE_VALF, and
       ±HUGE_VALL, respectively, with the same sign as the  correct  value  of
       the function.

       If the correct value would cause underflow, and is not representable, a
       range error may occur, and pow(), powf(), and powl() shall return  0.0,
       or  (if	IEC  60559 Floating-Point is not supported) an implementation-
       defined value no	 greater  in  magnitude	 than  DBL_MIN,	 FLT_MIN,  and
       LDBL_MIN, respectively.

       For  y < 0, if x is zero, a pole error may occur and pow(), powf(), and
       powl() shall return  ±HUGE_VAL,	±HUGE_VALF,  and  ±HUGE_VALL,  respec‐
       tively.	 On  systems that support the IEC 60559 Floating-Point option,
       if x is ±0, a pole error shall occur  and  pow(),  powf(),  and	powl()
       shall  return  ±HUGE_VAL, ±HUGE_VALF, and ±HUGE_VALL, respectively if y
       is an odd integer, or HUGE_VAL, HUGE_VALF, and HUGE_VALL,  respectively
       if y is not an odd integer.

       If x or y is a NaN, a NaN shall be returned (unless specified elsewhere
       in this description).

       For any value of y (including NaN), if x is +1, 1.0 shall be returned.

       For any value of x (including NaN), if y is ±0, 1.0 shall be returned.

       For any odd integer value of y > 0, if x is ±0, ±0 shall be returned.

       For y > 0 and not an odd integer, if x is ±0, +0 shall be returned.

       If x is −1, and y is ±Inf, 1.0 shall be returned.

       For |x| < 1, if y is −Inf, +Inf shall be returned.

       For |x| > 1, if y is −Inf, +0 shall be returned.

       For |x| < 1, if y is +Inf, +0 shall be returned.

       For |x| > 1, if y is +Inf, +Inf shall be returned.

       For y an odd integer < 0, if x is −Inf, −0 shall be returned.

       For y < 0 and not an odd integer, if x is −Inf, +0 shall be returned.

       For y an odd integer > 0, if x is −Inf, −Inf shall be returned.

       For y > 0 and not an odd integer, if x is −Inf, +Inf shall be returned.

       For y < 0, if x is +Inf, +0 shall be returned.

       For y > 0, if x is +Inf, +Inf shall be returned.

       If the correct value would cause underflow,  and	 is  representable,  a
       range error may occur and the correct value shall be returned.

ERRORS
       These functions shall fail if:

       Domain Error
		   The value of x is negative and y is a finite non-integer.

		   If  the  integer expression (math_errhandling & MATH_ERRNO)
		   is non-zero, then errno shall be set	 to  [EDOM].   If  the
		   integer  expression	(math_errhandling & MATH_ERREXCEPT) is
		   non-zero, then the invalid floating-point  exception	 shall
		   be raised.

       Pole Error  The value of x is zero and y is negative.

		   If  the  integer expression (math_errhandling & MATH_ERRNO)
		   is non-zero, then errno shall be set to [ERANGE].   If  the
		   integer  expression	(math_errhandling & MATH_ERREXCEPT) is
		   non-zero, then the divide-by-zero floating-point  exception
		   shall be raised.

       Range Error The result overflows.

		   If  the  integer expression (math_errhandling & MATH_ERRNO)
		   is non-zero, then errno shall be set to [ERANGE].   If  the
		   integer  expression	(math_errhandling & MATH_ERREXCEPT) is
		   non-zero, then the overflow floating-point exception	 shall
		   be raised.

       These functions may fail if:

       Pole Error  The value of x is zero and y is negative.

		   If  the  integer expression (math_errhandling & MATH_ERRNO)
		   is non-zero, then errno shall be set to [ERANGE].   If  the
		   integer  expression	(math_errhandling & MATH_ERREXCEPT) is
		   non-zero, then the divide-by-zero floating-point  exception
		   shall be raised.

       Range Error The result underflows.

		   If  the  integer expression (math_errhandling & MATH_ERRNO)
		   is non-zero, then errno shall be set to [ERANGE].   If  the
		   integer  expression	(math_errhandling & MATH_ERREXCEPT) is
		   non-zero, then the underflow floating-point exception shall
		   be raised.

       The following sections are informative.

EXAMPLES
       None.

APPLICATION USAGE
       On   error,   the   expressions	(math_errhandling  &  MATH_ERRNO)  and
       (math_errhandling & MATH_ERREXCEPT) are independent of each other,  but
       at least one of them must be non-zero.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       exp(), feclearexcept(), fetestexcept(), isnan()

       The Base Definitions volume of POSIX.1‐2008, Section 4.19, Treatment of
       Error Conditions for Mathematical Functions, <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 Electri‐
       cal 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.ker‐
       nel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group		     2013			       POW(3P)
[top]

List of man pages available for Archlinux

Copyright (c) for man pages and the logo by the respective OS vendor.

For those who want to learn more, the polarhome community provides shell access and support.

[legal] [privacy] [GNU] [policy] [cookies] [netiquette] [sponsors] [FAQ]
Tweet
Polarhome, production since 1999.
Member of Polarhome portal.
Based on Fawad Halim's script.
....................................................................
Vote for polarhome
Free Shell Accounts :: the biggest list on the net