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This noncompliant code example leads to to undefined behavior if 16 if the integral part of f_a cannot be represented as an integer:

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As a result of these conversions, it is possible that d_a is outside the range of values that can be represented by a float or that big_d is outside the range of values that can be represented as either a float or a double. If this is the case, the result is is undefined on behavior 17 on implementations that do not support Annex F, "IEC 60559 Floating-Point Arithmetic."

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Converting a floating-point value to a floating-point value of a smaller range and precision or to an integer type, or converting an integer type to a floating-point type, can result in a value that is not representable in the destination type and is undefined behavior on implementations that do not support Annex F.

Rule	Severity	Likelihood	Detectable	RepairableRemediation Cost	Priority	Level
FLP34-C	Low	Unlikely	Yes	LowYes	P3	L3

Automated Detection

Tool

Version

Checker

Description

Astrée

Include Page

	Astrée_V
	Astrée_V

Supported

Astrée reports all potential overflows resulting from floating-point conversions.

Compass/ROSE

Can detect some violations of this rule. However, it does not flag implicit casts, only explicit ones

CodeSonar

Include Page

	CodeSonar_V
	CodeSonar_V

LANG.TYPE.IAT

Inappropriate Assignment Type

Coverity

Include Page

	Coverity_V
	Coverity_V

MISRA_CAST (needs verification)

Can detect instances where implicit float conversion is involved: implicitly converting a complex expression with integer type to floating type, implicitly converting a double expression to narrower float type (may lose precision), implicitly converting a complex expression from float to double, implicitly converting from float to double in a function argument, and so on

Cppcheck

Include Page

	Cppcheck_V
	Cppcheck_V

floatConversionOverflow

suspiciousFloatingPointCast

Cppcheck Premium

Include Page

	Cppcheck Premium_V
	Cppcheck Premium_V

floatConversionOverflow

suspiciousFloatingPointCast

Helix QAC

Include Page

	Helix QAC_V
	Helix QAC_V

C4450, C4451, C4452, C4453, C4454, C4462, C4465

C++3011

Klocwork

Include Page

	Klocwork_V
	Klocwork_V

MISRA.CAST.FLOAT.WIDER
MISRA.CAST.FLOAT.INT
MISRA.CAST.INT_FLOAT
MISRA.CONV.FLOAT

LDRA tool suite

Include Page

	LDRA_V
	LDRA_V

435 S, 93 S

Partially implemented

Parasoft C/C++test

Include Page

	Parasoft_V
	Parasoft_V

CERT_C-FLP34-a
CERT_C-FLP34-b

Avoid implicit conversions from wider to narrower floating type
Avoid implicit conversions of floating point numbers from wider to narrower floating type

PC-lint Plus

Include Page