**CIGAL Reference Manual, Chapter 3 (Functions): qstnmrk**
===== ? -- “Query” operator – gets status of operand=====
**usage:**

The QUERY operator tests the status of a variable.  Its value is:
  .      -1      if the variable is undefined
         0      if the variable is defined but empty (size=0)
        >0      if the variable is defined and non-empty, the number of
                 elements is returned

The QUERY operator is very similar to the SIZE function; however, unlike the SIZE function, 
the QUERY operator can be used as an argument to another function (eg., IF).

Examples:
      if(?cmdlin > 0) exec cmdlin     ; execute CMDLIN string if not empty

      if(?ddflag < 0) {               ; create variables if undefined
          declare global integer ddflag
          declare global byte matrix ddbuf
      }

**See Also:**\\
[[jvs:cigal|CIGAL Home]], 
[[jvs:cigal:manual|CIGAL Manual]], 
[[jvs:cigal:manual:chapter3|Functions List]], 
[[jvs:cigal:manual:help|Manual Help]]