smash::DisableFloatTraps Class Reference

#include <fpenvironment.h>

Guard type that safely disables floating point traps for the scope in which it is placed.

Example:

{
  // some code where FPEs will trap
  DisableFloatTraps guard;
  // all code up to the closing brace will not trap anymore.
}

You can also keep some traps enabled. E.g. FE_DIVBYZERO is a candidate you might want to keep enabled, whereas FE_UNDERFLOW and FE_OVERFLOW are the ones that you really need to get rid of:

DisableFloatTraps guard(FE_DIVBYZERO | FE_INVALID);

Note

There is no guarantee about the complexity of modifying the floating point environment. This could be very expensive. Therefore it is always preferable to fix your code to not require underflow or overflow.

See also

http://en.cppreference.com/w/cpp/numeric/fenv/FE_exceptions for a complete list of flags.

Definition at line 79 of file fpenvironment.h.

Collaboration diagram for smash::DisableFloatTraps:

Public Member Functions
	DisableFloatTraps (int mask=0)
	Constructs the guard object. More...
	~DisableFloatTraps ()
	When the guard goes out of scope the floating point environment is restored. More...

Private Member Functions
void	reenable_traps (int mask)
	Reenables the given traps. More...

Private Attributes
std::fenv_t	environment_
	The stored environment that the destructor will restore. More...

Constructor & Destructor Documentation

DisableFloatTraps()

smash::DisableFloatTraps::DisableFloatTraps ( int  mask = 0 )

inlineexplicit

Constructs the guard object.

Parameters

mask	A bitwise of the traps you want to keep enabled.

Returns

The constructed object.

Definition at line 87 of file fpenvironment.h.

                                           {
    std::feholdexcept(&environment_);
    if (mask != 0) {
      reenable_traps(mask);
    }
  }

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~DisableFloatTraps()

smash::DisableFloatTraps::~DisableFloatTraps ( )

inline

When the guard goes out of scope the floating point environment is restored.

Definition at line 98 of file fpenvironment.h.

{ std::fesetenv(&environment_); }

Member Function Documentation

reenable_traps()

void smash::DisableFloatTraps::reenable_traps ( int  mask )

private

Reenables the given traps.

Parameters

mask	A bitwise of the traps you want to keep enabled.

Definition at line 62 of file fpenvironment.cc.

                                               {
  if (!enable_float_traps(mask)) {
    const auto &log = logger<LogArea::Fpe>();
    log.warn("Failed to setup traps on ", mask);
  }
}

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Member Data Documentation

environment_

std::fenv_t smash::DisableFloatTraps::environment_

private

The stored environment that the destructor will restore.

Definition at line 108 of file fpenvironment.h.

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The documentation for this class was generated from the following files:

• src/include/smash/fpenvironment.h
• src/fpenvironment.cc