New page.

Created after removing the erfc() material from erf.3.
Documents the complementary error function.

diff --git a/man3/erfc.3 b/man3/erfc.3
index fc5471fcbb3e1585fd51bfeb66fb0ce0e826c9c5..fe540f2c11a3a6ccc41f0f61470f98a401919b50 100644 (file)
--- a/man3/erfc.3
+++ b/man3/erfc.3
@@ -1 +1,126 @@
-.so man3/erf.3
+.\" Copyright 2008, Linux Foundation, written by Michael Kerrisk
+.\"     <mtk.manpages@gmail.com>
+.\"
+.\" Permission is granted to make and distribute verbatim copies of this
+.\" manual provided the copyright notice and this permission notice are
+.\" preserved on all copies.
+.\"
+.\" Permission is granted to copy and distribute modified versions of this
+.\" manual under the conditions for verbatim copying, provided that the
+.\" entire resulting derived work is distributed under the terms of a
+.\" permission notice identical to this one.
+.\"
+.\" Since the Linux kernel and libraries are constantly changing, this
+.\" manual page may be incorrect or out-of-date.  The author(s) assume no
+.\" responsibility for errors or omissions, or for damages resulting from
+.\" the use of the information contained herein.  The author(s) may not
+.\" have taken the same level of care in the production of this manual,
+.\" which is licensed free of charge, as they might when working
+.\" professionally.
+.\"
+.\" Formatted or processed versions of this manual, if unaccompanied by
+.\" the source, must acknowledge the copyright and authors of this work.
+.\"
+.TH ERFC 3  2008-07-29 "GNU" "Linux Programmer's Manual"
+.SH NAME
+erfc, erfcf, erfcl \- complementary error function
+.SH SYNOPSIS
+.nf
+.B #include <math.h>
+
+.BI "double erfc(double " x );
+.BI "float erfcf(float " x );
+.BI "long double erfcl(long double " x );
+
+.fi
+Link with \fI\-lm\fP.
+.sp
+.in -4n
+Feature Test Macro Requirements for glibc (see
+.BR feature_test_macros (7)):
+.in
+.sp
+.ad l
+.BR erfc ():
+_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE || _ISOC99_SOURCE; or
+.I cc\ -std=c99
+.br
+.BR erfcf (),
+.BR erfcl ():
+_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE\ >=\ 600|| _ISOC99_SOURCE; or
+.I cc\ -std=c99
+.ad b
+.SH DESCRIPTION
+The
+.BR erfc ()
+function returns the complementary error function of
+.IR x ,
+that is, 1.0 \- erf(x).
+.SH RETURN VALUE
+On success, these functions return the complementary error function of
+.IR x ,
+a value in the range [0,2].
+
+If
+.I x
+is a NaN, a NaN is returned.
+
+If
+.I x
+is +0 or \-0, 1 is returned.
+
+If
+.I x
+is positive infinity,
++0 is returned.
+
+If
+.I x
+is negative infinity,
++2 is returned.
+
+If the function result underflows and produces an unrepresentable value,
+the return value is 0.0.
+
+If the function result underflows but produces a representable
+(i.e., subnormal) value,
+.\" e.g., erfc(27) on x86-32
+that value is returned, and
+a "range error" occurs.
+.SH ERRORS
+See
+.BR math_error (7)
+for information on how to determine whether an error has occurred
+when calling these functions.
+.PP
+The following errors can occur:
+.TP
+Range error: result underflow (result is subnormal)
+.\" .I errno
+.\" is set to
+.\" .BR ERANGE .
+An underflow floating-point exception
+.RB ( FE_UNDERFLOW )
+is raised.
+.PP
+These functions do not set
+.IR errno .
+.\" FIXME . Is it intentional that these functions do not set errno?
+.\" Bug raised: http://sources.redhat.com/bugzilla/show_bug.cgi?id=6785
+.SH "CONFORMING TO"
+C99, POSIX.1-2001.
+The variant returning
+.I double
+also conforms to
+SVr4, 4.3BSD.
+.SH NOTES
+The
+.BR erfc ()
+functions are provided to avoid the loss accuracy that
+would occur for the calculation 1-erf(x) for large values of
+.IR x
+(for which the value of erf(x) approaches 1).
+.SH "SEE ALSO"
+.BR cerf (3),
+.BR erf (3),
+.BR exp (3)