Brain Imaging & Analysis Center

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:
CIGAL Home, CIGAL Manual, Functions List, Manual Help