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Allow negative operand for left shifts (-allow-negative-operand-in-shift)

Allow left shift operations on a negative number

Description

This option affects a Code Prover analysis only.

Specify that the verification must allow left shift operations on a negative number.

Set Option

User interface (desktop products only): In your project configuration, the option is on the Check Behavior node.

User interface (Polyspace Platform, desktop products only): In your project configuration, the option is on the Static Analysis tab on the Run Time Errors > Check Behavior node.

Command line and options file: Use the option -allow-negative-operand-in-shift. See Command-Line Information.

Why Use This Option

According to the C99 standard (sec 6.5.7), the result of a left shift operation on a negative number is undefined. Following the standard, the verification produces a red check on left shifts of negative numbers.

If your compiler has a well-defined behavior for left shifts of negative numbers, set this option. Note that allowing left shifts of negative numbers can reduce the cross-compiler portability of your code.

Settings

On

The verification allows shift operations on a negative number, for instance, -2 << 2.

Off (default)

If a shift operation is performed on a negative number, the verification generates an error.

Command-Line Information

Parameter: -allow-negative-operand-in-shift
Default: Off
Example (Code Prover): polyspace-code-prover -sources file_name -allow-negative-operand-in-shift
Example (Code Prover Server): polyspace-code-prover-server -sources file_name -allow-negative-operand-in-shift

See Also

Topics