QA·C Help - 4443

	4443	A non-constant expression of 'essentially unsigned' type (%1s) is being converted to a wider signed type, '%2s' on assignment.

Arithmetic type - Assignment

This message is issued whenever a non-constant expression of essentially unsigned type undergoes an assigning conversion to a wider signed integer type, i.e. the configured size (with -s option) of the unsigned type is lower than that of the signed type.

For example:


/*PRQA S 1-9999 ++*/
/*PRQA S 4443 --*/

void foo (int b);

int f4443 (unsigned short a)
{
  int sia = a;              /* 4443 */

  foo (a + 1u);             /* 4443 */

  sia = (a - 1u);           /* 4443 */

  return a;                 /* 4443 */
}

This message identifies a safe (widening) conversion, assuming the conversion is intentional. In this case it may be better to document the conversion with an explicit cast. Message 4446 is generated for other unsigned to signed conversions, highlighting potential data loss.

MISRA-C:2004 Rules applicable to message 4443:

Rule 10.1 (Required)

The value of an expression of integer type shall not be implicitly converted to a different underlying type if: a) it is not a conversion to a wider integer type of the same signedness, or b) the expression is complex, or c) the expression is not constant and is a function argument, or d) the expression is not constant and is a return expression