QB64 is a modern extended BASIC programming language that retains QBasic/QuickBASIC 4.5 compatibility and compiles native binaries for Windows, Linux, and macOS.

CALL sends code execution to a subroutine procedure in a program. In QB64 the subroutine doesn’t need to be declared.


CALL ProcedureName (parameter1, parameter2,…)]

Alternative Syntax

ProcedureName parameter1, parameter2,…]


How parameters are passed in two SUB calls, one with CALL using brackets and one without CALL or brackets:

DIM a AS INTEGER 'value not shared with SUB
DIM SHARED b AS INTEGER 'value shared with any SUB
a = 1
b = 2
c = 3

CALL helloworld (a) 'a passed to c parameter with CALL
helloworld a        'a passed to c parameter w/o CALL


SUB helloworld (c) 'SUB parameter variables are always inside of brackets in SUB code
PRINT "Hello World!"
PRINT a,  b, c
a = a + 1 'a is a SUB value of 0 when printed which may increase inside SUB only 
b = b + 1 'b is a shared value which can increase anywhere
c = c + 1 'c is a SUB parameter value from a in calls which may increase inside SUB only


Hello World!
 0            2            1
Hello World!
 0            3            1 

Explanation: Variable a that is outside of the subroutine isn’t SHARED so it will have no effect inside the subroutine, the variable a inside the subroutine is only valid inside the subroutine, and whatever value a has outside of it makes no difference within the subroutine.

The variable b on the other hand is SHARED with the subroutines and thus can be changed in the subroutine. The variable a is initiated with 0 as default when created, thus it will return 0 since it wasn’t changed within the subroutine.

The variable c is the SUB parameter variable that passes values into the sub. Its value could be changed by the passed parameter value or inside of the subroutine. The un-shared c variable value outside of the sub is irrelevant within the subroutine.

See Also