Article ID: 49388
Article Last Modified on 11/21/2006
APPLIES TO
- Microsoft QuickBasic 4.0
- Microsoft QuickBASIC 4.0b
- Microsoft QuickBasic 4.5 for MS-DOS
- Microsoft BASIC Compiler 6.0
- Microsoft BASIC Compiler 6.0b
- Microsoft BASIC Professional Development System 7.0
- Microsoft BASIC Professional Development System 7.1
This article was previously published under Q49388
SUMMARY
The two programs below demonstrate how Microsoft Basic and assembly language pass fixed-length strings by near reference.
This information about interlanguage calling applies to QuickBasic versions 4.00, 4.00b, and 4.50 for MS-DOS, to Microsoft Basic Compiler versions 6.00 and 6.00b for MS-DOS and MS OS/2, and to Microsoft Basic Professional Development System (PDS) versions 7.00 and 7.10 for MS-DOS and MS OS/2.
MORE INFORMATION
For more information about passing other types of parameters between Basic and MASM, search in the Microsoft Knowledge Base using the following word:
BAS2MASM
Code Example
The following Basic program is BFSTRN.BAS, which creates a fixed-length string that is passed to assembly language to print and receives a fixed-length string from assembly:
DECLARE SUB RString(BYVAL offs AS INTEGER)
TYPE fixstring
s AS STRING * 20
END TYPE
DIM a AS STRING * 20
CLS
a = "Basic String$" ' "$" terminates string for assembly
CALL RString(VARPTR(a))
END
SUB BasicSub(a AS fixstring)
LOCATE 2, 1 ' Must LOCATE because print in assembly won't move
PRINT a.s ' Basic's screen position
END SUB
The following program is AFSTRN.ASM, which gets a fixed-length string by near reference, prints the string, then passes a string to a Basic subprogram:
; The following handy .MODEL directive is found in MASM 5.10 but not
; in earlier versions:
.MODEL MEDIUM, Basic
EXTRN BasicSub:PROC
.DATA
astr DB 'Assembly String '
.CODE
PUBLIC RString
RString PROC
push bp
mov bp, sp ; set stack frame
mov dx, [bp+6] ; address of string
mov ah, 9 ; DOS interrupt to print string
int 21h
mov ax, OFFSET astr ; address of assembly string
push ax ; pass it to Basic
call BasicSub
pop bp
ret 2
RString ENDP
END
To demonstrate these programs from an .EXE program, compile and link as follows:
BC BFSTRN.BAS;
MASM AFSTRN.ASM;
LINK BFSTRN AFSTRN;
BFSTRN.EXE produces the following output:
Basic String
Assembly String
Additional query words: QuickBas BasicCom
Keywords: KB49388
