diff options
Diffstat (limited to 'upstream/archlinux/man3p/exp.3p')
| -rw-r--r-- | upstream/archlinux/man3p/exp.3p | 174 |
1 files changed, 174 insertions, 0 deletions
diff --git a/upstream/archlinux/man3p/exp.3p b/upstream/archlinux/man3p/exp.3p new file mode 100644 index 00000000..56a08d5b --- /dev/null +++ b/upstream/archlinux/man3p/exp.3p @@ -0,0 +1,174 @@ +'\" et +.TH EXP "3P" 2017 "IEEE/The Open Group" "POSIX Programmer's Manual" +.\" +.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 +exp, +expf, +expl +\(em exponential function +.SH SYNOPSIS +.LP +.nf +#include <math.h> +.P +double exp(double \fIx\fP); +float expf(float \fIx\fP); +long double expl(long double \fIx\fP); +.fi +.SH 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\(hy2017 defers to the ISO\ C standard. +.P +These functions shall compute the base-\c +.IR e +exponential of +.IR x . +.P +An application wishing to check for error situations should set +.IR errno +to zero and call +.IR feclearexcept (FE_ALL_EXCEPT) +before calling these functions. On return, if +.IR errno +is non-zero or \fIfetestexcept\fR(FE_INVALID | FE_DIVBYZERO | +FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an error has occurred. +.SH "RETURN VALUE" +Upon successful completion, these functions shall return the +exponential value of +.IR x . +.P +If the correct value would cause overflow, a range error shall occur +and +\fIexp\fR(), +\fIexpf\fR(), +and +\fIexpl\fR() +shall return the value of the macro HUGE_VAL, HUGE_VALF, and HUGE_VALL, +respectively. +.P +If the correct value would cause underflow, +and is not representable, +a range error may occur, and +\fIexp\fR(), +\fIexpf\fR(), +and +\fIexpl\fR() +shall return +0.0, or +(if the IEC 60559 Floating-Point option is not supported) an +implementation-defined value no greater in magnitude than DBL_MIN, +FLT_MIN, and LDBL_MIN, respectively. +.P +If +.IR x +is NaN, a NaN shall be returned. +.P +If +.IR x +is \(+-0, 1 shall be returned. +.P +If +.IR x +is \-Inf, +0 shall be returned. +.P +If +.IR x +is +Inf, +.IR x +shall be returned. +.P +If the correct value would cause underflow, and is representable, a +range error may occur and the correct value shall be returned. +.SH ERRORS +These functions shall fail if: +.IP "Range\ Error" 12 +The result overflows. +.RS 12 +.P +If the integer expression (\fImath_errhandling\fR & MATH_ERRNO) is +non-zero, then +.IR errno +shall be set to +.BR [ERANGE] . +If the integer expression (\fImath_errhandling\fR & MATH_ERREXCEPT) is +non-zero, then the overflow floating-point exception shall be raised. +.RE +.P +These functions may fail if: +.IP "Range\ Error" 12 +The result underflows. +.RS 12 +.P +If the integer expression (\fImath_errhandling\fR & MATH_ERRNO) is +non-zero, then +.IR errno +shall be set to +.BR [ERANGE] . +If the integer expression (\fImath_errhandling\fR & MATH_ERREXCEPT) is +non-zero, then the underflow floating-point exception shall be raised. +.RE +.LP +.IR "The following sections are informative." +.SH EXAMPLES +.SS "Computing the Density of the Standard Normal Distribution" +.P +This function shows an implementation for the density of the standard +normal distribution using +\fIexp\fR(). +This example uses the constant M_PI which is part of the XSI option. +.sp +.RS 4 +.nf + +#include <math.h> +.P +double +normal_density (double x) +{ + return exp(-x*x/2) / sqrt (2*M_PI); +} +.fi +.P +.RE +.SH "APPLICATION USAGE" +On error, the expressions (\fImath_errhandling\fR & MATH_ERRNO) and +(\fImath_errhandling\fR & MATH_ERREXCEPT) are independent of each +other, but at least one of them must be non-zero. +.SH RATIONALE +None. +.SH "FUTURE DIRECTIONS" +None. +.SH "SEE ALSO" +.IR "\fIfeclearexcept\fR\^(\|)", +.IR "\fIfetestexcept\fR\^(\|)", +.IR "\fIisnan\fR\^(\|)", +.IR "\fIlog\fR\^(\|)" +.P +The Base Definitions volume of POSIX.1\(hy2017, +.IR "Section 4.20" ", " "Treatment of Error Conditions for Mathematical Functions", +.IR "\fB<math.h>\fP" +.\" +.SH COPYRIGHT +Portions of this text are reprinted and reproduced in electronic form +from IEEE Std 1003.1-2017, Standard for Information Technology +-- Portable Operating System Interface (POSIX), The Open Group Base +Specifications Issue 7, 2018 Edition, +Copyright (C) 2018 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 . +.PP +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 . |