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diff --git a/man-pages-posix-2017/man3p/expm1.3p b/man-pages-posix-2017/man3p/expm1.3p new file mode 100644 index 0000000..8db897e --- /dev/null +++ b/man-pages-posix-2017/man3p/expm1.3p @@ -0,0 +1,184 @@ +'\" et +.TH EXPM1 "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 +expm1, +expm1f, +expm1l +\(em compute exponential functions +.SH SYNOPSIS +.LP +.nf +#include <math.h> +.P +double expm1(double \fIx\fP); +float expm1f(float \fIx\fP); +long double expm1l(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 \fIe\u\s-3x\s+3\d\fR\-1.0. +.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 return +\fIe\s-3\ux\d\s+3\fR\-1.0. +.P +If the correct value would cause overflow, a range error shall occur +and +\fIexpm1\fR(), +\fIexpm1f\fR(), +and +\fIexpm1l\fR() +shall return the value of the macro HUGE_VAL, HUGE_VALF, and HUGE_VALL, +respectively. +.P +If +.IR x +is NaN, a NaN shall be returned. +.P +If +.IR x +is \(+-0, \(+-0 shall be returned. +.P +If +.IR x +is \-Inf, \-1 shall be returned. +.P +If +.IR x +is +Inf, +.IR x +shall be returned. +.P +If +.IR x +is subnormal, a range error may occur +.br +and +.IR x +should be returned. +.P +If +.IR x +is not returned, +\fIexpm1\fR(), +\fIexpm1f\fR(), +and +\fIexpm1l\fR() +shall return an implementation-defined value no greater in magnitude +than DBL_MIN, FLT_MIN, and LDBL_MIN, respectively. +.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 value of +.IR x +is subnormal. +.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 +None. +.SH "APPLICATION USAGE" +The value of +.IR expm1 ( x ) +may be more accurate than +.IR exp ( x )\-1.0 +for small values of +.IR x . +.P +The +\fIexpm1\fR() +and +\fIlog1p\fR() +functions are useful for financial calculations of +((1+\fIx\fR)\u\s-3\fIn\fR\s+3\d\-1)/\fIx\fR, namely: +.sp +.RS 4 +.nf + +expm1(\fIn\fP * log1p(\fIx\fP))/\fIx\fP +.fi +.P +.RE +.P +when +.IR x +is very small (for example, when calculating small daily interest +rates). These functions also simplify writing accurate inverse +hyperbolic functions. +.P +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 "\fIexp\fR\^(\|)", +.IR "\fIfeclearexcept\fR\^(\|)", +.IR "\fIfetestexcept\fR\^(\|)", +.IR "\fIilogb\fR\^(\|)", +.IR "\fIlog1p\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 . |