warn_possunwant

Controls the recognition of possible unintentional logical errors.

  #pragma warn_possunwant on | off | reset  

If you enable this pragma, the compiler checks for common, unintended logical errors:

• An assignment in either a logical expression or the conditional portion of an if, while, or for expression. This warning message is useful if you use = when you mean to use ==. The following listing shows an example.
  Listing: Confusing = and == in Comparisons

  if (a=b) f(); /* WARNING: a=b is an assignment. */
  if ((a=b)!=0) f(); /* OK: (a=b)!=0 is a comparison. */
  
  if (a==b) f(); /* OK: (a==b) is a comparison. */
  

• An equal comparison in a statement that contains a single expression. This check is useful if you use == when you meant to use =. The following listing shows an example.
  Listing: Confusing = and == Operators in Assignments

  a == 0;        // WARNING: This is a comparison.
  a = 0;         // OK: This is an assignment, no warning
  

• A semicolon ( ;) directly after a while, if, or for statement.

  For example, The following listing generates a warning message.

  Listing: Empty statement

  i = sockcount();
  while (--i);  /* WARNING: empty loop. */
  
      matchsock(i);
  

  If you intended to create an infinite loop, put white space or a comment between the while statement and the semicolon. The statements in the following suppress the above error or warning messages.

  Listing: Intentional empty statements

  while (i++) ; /* OK: White space separation. */
  while (i++) /* OK: Comment separation */ ;