1 files changed, 122 insertions, 0 deletions
diff --git a/man3/acos.3 b/man3/acos.3
new file mode 100644
index 0000000..a81b4ef
--- /dev/null
+++ b/man3/acos.3
@@ -0,0 +1,122 @@
+'\" t
+.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
+.\" and Copyright 2008, Linux Foundation, written by Michael Kerrisk
+.\"     <mtk.manpages@gmail.com>
+.\"
+.\" SPDX-License-Identifier: Linux-man-pages-copyleft
+.\"
+.\" References consulted:
+.\"     Linux libc source code
+.\"     Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
+.\"     386BSD man pages
+.\" Modified 1993-07-24 by Rik Faith (faith@cs.unc.edu)
+.\" Modified 2002-07-25 by Walter Harms
+.\" 	(walter.harms@informatik.uni-oldenburg.de)
+.\"
+.TH acos 3 2023-07-20 "Linux man-pages 6.05.01"
+.SH NAME
+acos, acosf, acosl \- arc cosine function
+.SH LIBRARY
+Math library
+.RI ( libm ", " \-lm )
+.SH SYNOPSIS
+.nf
+.B #include <math.h>
+.PP
+.BI "double acos(double " x );
+.BI "float acosf(float " x );
+.BI "long double acosl(long double " x );
+.fi
+.PP
+.RS -4
+Feature Test Macro Requirements for glibc (see
+.BR feature_test_macros (7)):
+.RE
+.PP
+.BR acosf (),
+.BR acosl ():
+.nf
+    _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
+        || /* Since glibc 2.19: */ _DEFAULT_SOURCE
+        || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
+.fi
+.SH DESCRIPTION
+These functions calculate the arc cosine of
+.IR x ;
+that is
+the value whose cosine is
+.IR x .
+.SH RETURN VALUE
+On success, these functions return the arc cosine of
+.I x
+in radians; the return value is in the range [0,\ pi].
+.PP
+If
+.I x
+is a NaN, a NaN is returned.
+.PP
+If
+.I x
+is +1,
++0 is returned.
+.PP
+If
+.I x
+is positive infinity or negative infinity,
+a domain error occurs,
+and a NaN is returned.
+.PP
+If
+.I x
+is outside the range [\-1,\ 1],
+a domain error occurs,
+and a NaN is returned.
+.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
+Domain error: \fIx\fP is outside the range [\-1,\ 1]
+.I errno
+is set to
+.BR EDOM .
+An invalid floating-point exception
+.RB ( FE_INVALID )
+is raised.
+.SH ATTRIBUTES
+For an explanation of the terms used in this section, see
+.BR attributes (7).
+.TS
+allbox;
+lbx lb lb
+l l l.
+Interface	Attribute	Value
+T{
+.na
+.nh
+.BR acos (),
+.BR acosf (),
+.BR acosl ()
+T}	Thread safety	MT-Safe
+.TE
+.sp 1
+.SH STANDARDS
+C11, POSIX.1-2008.
+.SH HISTORY
+C99, POSIX.1-2001.
+.PP
+The variant returning
+.I double
+also conforms to
+C89, SVr4, 4.3BSD.
+.SH SEE ALSO
+.BR asin (3),
+.BR atan (3),
+.BR atan2 (3),
+.BR cacos (3),
+.BR cos (3),
+.BR sin (3),
+.BR tan (3)