FERAISEEXCEPT(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
feraiseexcept — raise floating-point exception

SYNOPSIS

#include <fenv.h>

int feraiseexcept(int excepts);

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.1-2017 defers to the ISO C standard.

The feraiseexcept() function shall attempt to raise the supported floating-point exceptions represented by the excepts argument. The order in which these floating-point exceptions are raised is unspecified, except that if the excepts argument represents IEC 60559 valid coincident floating-point exceptions for atomic operations (namely overflow and inexact, or underflow and inexact), then overflow or underflow shall be raised before inexact. Whether the feraiseexcept() function additionally raises the inexact floating-point exception whenever it raises the overflow or underflow floating-point exception is implementation-defined.

RETURN VALUE
If the argument is zero or if all the specified exceptions were successfully raised, feraiseexcept() shall return zero. Otherwise, it shall return a non-zero value.

ERRORS
No errors are defined.

The following sections are informative.

EXAMPLES
None.

APPLICATION USAGE
The effect is intended to be similar to that of floating-point exceptions raised by arithmetic operations. Hence, enabled traps for floating-point exceptions raised by this function are taken.

RATIONALE
Raising overflow or underflow is allowed to also raise inexact because on some architectures the only practical way to raise an exception is to execute an instruction that has the exception as a side-effect. The function is not restricted to accept only valid coincident expressions for atomic operations, so the function can be used to raise exceptions accrued over several operations.

FUTURE DIRECTIONS
None.

SEE ALSO
feclearexcept(), fegetexceptflag(), fetestexcept()

The Base Definitions volume of POSIX.1-2017, <fenv.h>

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 .

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 .