CACOS(3P) | POSIX Programmer's Manual | CACOS(3P) |

# 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.# NAME

cacos, cacosf, cacosl - complex arc cosine functions# SYNOPSIS

**#include <complex.h>**

*z*

**);**

*z*

**);**

*z*

**);**

# DESCRIPTION

These functions shall compute the complex arc cosine of*z*, with branch cuts outside the interval [-1, +1] along the real axis.

# RETURN VALUE

These functions shall return the complex arc cosine value, in the range of a strip mathematically unbounded along the imaginary axis and in the interval [0, pi] along the real axis.# ERRORS

No errors are defined. *The following sections are informative.*

# EXAMPLES

None.# APPLICATION USAGE

None.# RATIONALE

None.# FUTURE DIRECTIONS

None.# SEE ALSO

*ccos*(), the Base Definitions volume of IEEE Std 1003.1-2001,

*<complex.h>*

# 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 .2003 | IEEE/The Open Group |