Article ID: 48207
Article Last Modified on 8/16/2005
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 Q48207
SUMMARY
The two programs below demonstrate how Microsoft C can create and pass both fixed-length and variable-length strings to Microsoft Basic.
This information about interlanguage calling applies to QuickBasic versions 4.00, 4.00b, 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.
For Basic PDS 7.00 and 7.10, this example works only with near strings. If you are using far strings (BC /Fs compile switch or in QBX.EXE), you must use the string-manipulation routines provided with Basic PDS 7.00 and 7.10 to change variable-length strings (StringAssign, StringRelease, StringAddress, and StringLength). For more information about using far strings, see Chapter 13 of the "Microsoft Basic 7.0: Programmer's Guide" for versions 7.00 and 7.10.
MORE INFORMATION
For more information about passing other types of parameters between Basic and C and a list of which Basic and C versions are compatible with each other, search in the Microsoft Knowledge Base using the following word:
BAS2C
Code Example
The following Basic program is BSUB.BAS, which invokes a C routine that creates two strings and passes them to a Basic subroutine. The Basic subroutine prints out the string (and the string's length) received from the C routine.
DECLARE SUB CSUB CDECL() TYPE fixstringtype ' Must use type to pass fixed-length string B AS STRING * 26 ' in parameter list. END TYPE CALL CSUB END SUB BASSUB(A$, B AS fixstringtype) ' Subroutine called from C PRINT A$ PRINT LEN(A$) PRINT B.B PRINT LEN(B.B) END SUB
The following program is CSUB.C, which builds a string descriptor that is passed to a called Basic subroutine:
#include <string.h> struct stringdesc { int length; /* string length */ char *string; /* near address of the string */ }; extern void pascal bassub(struct stringdesc *basstring, char *basfixstring); struct stringdesc *std; char thesecondstring[26]; void csub() { /* create the strings */ std->length = 18; strcpy(std->string, "This is the string"); strcpy(thesecondstring, "This is the second string"); bassub(std, thesecondstring); /* call Basic subroutine */ }
To demonstrate these programs from an .EXE program, compile and link as follows:
BC BSUB.BAS; CL /c /AM CSUB.C; LINK /NOE BSUB CSUB;
BSUB.EXE produces the following output:
This is the string 18 This is the second string 26
Additional query words: QuickBas BasicCom
Keywords: KB48207