Important Notice

The pages on this site contain documentation for very old MS-DOS software, purely for historical purposes. If you're looking for up-to-date documentation, particularly for programming, you should not rely on the information found here, as it will be woefully out of date.

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 Syntax 1: For Non-Array Arguments
 CALL name [([[{BYVAL|SEG}] argument] [,[{BYVAL|SEG}] argument])]...
 CALLS name [argument] [,argument]...
 
 Syntax 2: For Array Arguments
 CALL name [([argument[()]] [, argument[()]])]...
 name [argument[()]] [, argument[()]]...
 
 Usage Notes
   ■ The CALL keyword is optional when you use the CALL statement. When you
     omit CALL, you must declare the procedure in a DECLARE statement. If you
     dont't, when you save the program, Visual Basic automatically generates
     a DECLARE statement for you. When you omit CALL, you must omit the
     parentheses around the argument list.
 
    ■ CALLS is the same as using CALL with a SEG keyword before each argument;
     every argument in a CALLS statement is passed as a segmented address.
 
   ■ If name refers to an assembly-language procedure, it must be a name
     declared with PUBLIC (symbol).
 
   ■ The result of the BYVAL keyword differs from Visual Basic's pass by
     value:
 
         CALL Difference (BYVAL A,(B))
 
     For the first argument, only the value of A is passed to Difference. In
     contrast, (B) is evaluated, a temporary location is created for the
     value, and the address of the temporary location is passed to
     Difference.
 
   ■ You can use Visual Basic's pass by value for an argument, but the
     procedure in the other language must accept an address, because the
     address of the temporary location is passed.
 
   ■ Be careful using the SEG keyword to pass elements of arrays because
     Visual Basic may move arrays in memory before the called routine starts
     to execute. Anything in an argument list that causes memory movement may
     create problems. You can safely pass variables using SEG if the
     argument list for the CALL statement contains only simple variables,
     arithmetic expressions, or arrays indexed without the use of intrinsic
     or defined functions.