fpe

Architecture Restrictions

Not available on Intel® 64 architecture targeting the Intel® Xeon Phi™ coprocessor x100 product family (formerly code name Knights Corner)

Syntax

Linux and macOS:

-fpen

Windows:

/fpe:n

Arguments

n

Specifies the floating-point exception handling level. Possible values are:

0

Floating-point invalid, divide-by-zero, and overflow exceptions are enabled throughout the application when the main program is compiled with this value. If any such exceptions occur, execution is aborted. This option causes denormalized floating-point results to be set to zero. Underflow results will also be set to zero, unless you override this by explicitly specifying option -no-ftz or -fp-model precise (Linux* and OS X*) or option /Qftz- or /fp:precise (Windows*).

Underflow results from SSE instructions, as well as x87 instructions, will be set to zero. By contrast, option [Q]ftz only sets SSE underflow results to zero.

Sets option -fp-speculation=strict (Linux* and OS X*) or /Qfp-speculation:strict (Windows*) for any program unit compiled with -fpe0 (Linux* and OS X*) or /fpe:0 (Windows*). This disables certain optimizations in cases where speculative execution of floating-point operations could lead to floating-point exceptions that would not occur in the absence of speculation. For example, this may prevent the vectorization of some loops containing conditionals.

To get more detailed location information about where the error occurred, use option traceback.

1

All floating-point exceptions are disabled.

Underflow results from SSE instructions, as well as x87 instructions, will be set to zero.

3

All floating-point exceptions are disabled. Floating-point underflow is gradual, unless you explicitly specify a compiler option that enables flush-to-zero, such as [Q]ftz, O3, or O2. This setting provides full IEEE support.

Default

-fpe3 or /fpe:3

All floating-point exceptions are disabled. Floating-point underflow is gradual, unless you explicitly specify a compiler option that enables flush-to-zero.

Description

This option allows some control over floating-point exception handling at run-time. This includes whether exceptional floating-point values are allowed and how precisely run-time exceptions are reported.

The fpe option affects how the following conditions are handled:

When floating-point calculations result in a divide by zero, overflow, or invalid operation.
When floating-point calculations result in an underflow.
When a denormalized number or other exceptional number (positive infinity, negative infinity, or a NaN) is present in an arithmetic expression.

When enabled exceptions occur, execution is aborted and the cause of the abort reported to the user. If compiler option traceback is specified at compile time, detailed information about the location of the abort is also reported.

This option does not enable underflow exceptions, input denormal exceptions, or inexact exceptions.

IDE Equivalent

Visual Studio: Floating-Point > Floating-Point Exception Handling

Eclipse: None

Xcode: Floating-Point > Floating-Point Exception Handling

Alternate Options

None

fpe