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diff --git a/man-pages-posix-2003/man3p/pow.3p b/man-pages-posix-2003/man3p/pow.3p new file mode 100644 index 0000000..517cf5a --- /dev/null +++ b/man-pages-posix-2003/man3p/pow.3p @@ -0,0 +1,186 @@ +.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved +.TH "POW" 3P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual" +.\" pow +.SH 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. +.SH NAME +pow, powf, powl \- power function +.SH SYNOPSIS +.LP +\fB#include <math.h> +.br +.sp +double pow(double\fP \fIx\fP\fB, double\fP \fIy\fP\fB); +.br +float powf(float\fP \fIx\fP\fB, float\fP \fIy\fP\fB); +.br +long double powl(long double\fP \fIx\fP\fB, long double\fP \fIy\fP\fB); +.br +\fP +.SH DESCRIPTION +.LP +These functions shall compute the value of \fIx\fP raised to the power +\fIy\fP, \fIx**y\fP. If +\fIx\fP is negative, the application shall ensure that \fIy\fP is +an integer value. +.LP +An application wishing to check for error situations should set \fIerrno\fP +to zero and call +\fIfeclearexcept\fP(FE_ALL_EXCEPT) before calling these functions. +On return, if \fIerrno\fP is non-zero or +\fIfetestexcept\fP(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) +is non-zero, an error has occurred. +.SH RETURN VALUE +.LP +Upon successful completion, these functions shall return the value +of \fIx\fP raised to the power \fIy\fP. +.LP +For finite values of \fIx\fP < 0, and finite non-integer values of +\fIy\fP, a domain error shall occur and either a NaN +(if representable), or an implementation-defined value shall be +returned. +.LP +If the correct value would cause overflow, a range error shall occur +and \fIpow\fP(), \fIpowf\fP(), and \fIpowl\fP() shall +return \(+-HUGE_VAL, \(+-HUGE_VALF, and \(+-HUGE_VALL, respectively, +with the same sign as the correct value of the +function. +.LP +If the correct value would cause underflow, and is not representable, +a range error may occur, and either 0.0 (if +supported), or an implementation-defined value shall be +returned. +.LP +If +\fIx\fP or \fIy\fP is a NaN, a NaN shall be returned (unless specified +elsewhere in this description). +.LP +For any value of \fIy\fP (including NaN), if \fIx\fP is +1, 1.0 shall +be returned. +.LP +For any value of \fIx\fP (including NaN), if \fIy\fP is \(+-0, 1.0 +shall be returned. +.LP +For any odd integer value of \fIy\fP > 0, if \fIx\fP is \(+-0, \(+-0 +shall be returned. +.LP +For \fIy\fP > 0 and not an odd integer, if \fIx\fP is \(+-0, +0 shall +be returned. +.LP +If \fIx\fP is -1, and \fIy\fP is \(+-Inf, 1.0 shall be returned. +.LP +For |\fIx\fP| < 1, if \fIy\fP is -Inf, +Inf shall be returned. +.LP +For |\fIx\fP| > 1, if \fIy\fP is -Inf, +0 shall be returned. +.LP +For |\fIx\fP| < 1, if \fIy\fP is +Inf, +0 shall be returned. +.LP +For |\fIx\fP| > 1, if \fIy\fP is +Inf, +Inf shall be returned. +.LP +For \fIy\fP an odd integer < 0, if \fIx\fP is -Inf, -0 shall be returned. +.LP +For \fIy\fP < 0 and not an odd integer, if \fIx\fP is -Inf, +0 shall +be returned. +.LP +For \fIy\fP an odd integer > 0, if \fIx\fP is -Inf, -Inf shall be +returned. +.LP +For \fIy\fP > 0 and not an odd integer, if \fIx\fP is -Inf, +Inf shall +be returned. +.LP +For \fIy\fP < 0, if \fIx\fP is +Inf, +0 shall be returned. +.LP +For \fIy\fP > 0, if \fIx\fP is +Inf, +Inf shall be returned. +.LP +For \fIy\fP an odd integer < 0, if \fIx\fP is \(+-0, a pole error +shall occur and \(+-HUGE_VAL, \(+-HUGE_VALF, +and \(+-HUGE_VALL shall be returned for \fIpow\fP(), \fIpowf\fP(), +and \fIpowl\fP(), respectively. +.LP +For \fIy\fP < 0 and not an odd integer, if \fIx\fP is \(+-0, a pole +error shall occur and HUGE_VAL, HUGE_VALF, and +HUGE_VALL shall be returned for \fIpow\fP(), \fIpowf\fP(), and \fIpowl\fP(), +respectively. +.LP +If the correct value would cause underflow, and is representable, +a range error may occur and the correct value shall be +returned. +.SH ERRORS +.LP +These functions shall fail if: +.TP 7 +Domain\ Error +The value of \fIx\fP is negative and \fIy\fP is a finite non-integer. +.LP +If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, +then \fIerrno\fP 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. +.TP 7 +Pole\ Error +The value of \fIx\fP is zero and \fIy\fP is negative. +.LP +If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, +then \fIerrno\fP 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. +.TP 7 +Range\ Error +The result overflows. +.LP +If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, +then \fIerrno\fP 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. +.sp +.LP +These functions may fail if: +.TP 7 +Range\ Error +The result underflows. +.LP +If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, +then \fIerrno\fP 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. +.sp +.LP +\fIThe following sections are informative.\fP +.SH EXAMPLES +.LP +None. +.SH APPLICATION USAGE +.LP +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. +.SH RATIONALE +.LP +None. +.SH FUTURE DIRECTIONS +.LP +None. +.SH SEE ALSO +.LP +\fIexp\fP(), \fIfeclearexcept\fP(), \fIfetestexcept\fP(), \fIisnan\fP(), +the Base Definitions volume of +IEEE\ Std\ 1003.1-2001, Section 4.18, Treatment of Error Conditions +for +Mathematical Functions, \fI<math.h>\fP +.SH COPYRIGHT +Portions of this text are reprinted and reproduced in electronic form +from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology +-- Portable Operating System Interface (POSIX), The Open Group Base +Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of +Electrical and Electronics Engineers, Inc and The Open Group. 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.opengroup.org/unix/online.html . |