StringAddress Routine
 ----------------------------------------------------------------------------


 Action

 Used in mixed-language programming to returns the far address of a
 variable-length string.


 Syntax



  far-address =  StringAddress( string-descriptor%);

 Remarks


 The syntax above is for the C language. For MASM, Pascal, and FORTRAN
 examples, see Chapter 13, "Mixed-Language Programming with Far Strings" in
 the  Programmer's Guide.

  StringAddress returns the far address of the variable-length string defined
 by  string-descriptor%. The argument  string-descriptor% is the near address
 of a string descriptor within a non-BASIC routine.

 A non-BASIC routine uses  StringAddress to find the far address of a BASIC
 variable-length string. Calls to the  StringAddress routine always are made
 from a non-BASIC routine to find the address of a string that was
 transferred to BASIC from the non-BASIC routine.

 For example, assume that you have passed a string from a MASM routine to
 BASIC's string space using  StringAssign. The descriptor for the string
 exists at offset descriptor. MASM can find the far address of the string
 data using the following code.

 leaax, descriptor ; offset of descriptor


 pushax


 extrnstringaddress. proc far


 callstringaddress




 The far address is returned in DX.AX. DX holds the segment and AX holds the
 offset.



 Note

 If you are not doing mixed-language programming, there usually is no reason
 to use  StringAddress. Instead, use  SSEGADD to find the far address of a
 variable-length string.

 For more information on mixed-language programming with strings, see Chapter
 12, "Mixed-Language Programming" and Chapter 13, "Mixed-Language Programming
 with Far Strings" in the  Programmer's  Guide.


 See Also

  SSEGADD,  StringAssign,  StringLength,  StringRelease


 Example


 The following example shows how to use  StringAddress and  StringLength,
 routines in the BASIC main library.

 The program creates a string in BASIC, then passes it to MASM, which uses
 StringAddress to find the data that needs to be printed. It uses
 StringLength to tell the system the length of the string.

 DEFINT A-Z


 ' Create a variable-length string.


 Message1$ = "This string was sent to MASM for printing."


 ' Pass it to MASM to be printed.


 CALL PrintMessage1(Message1$)




 The following MASM procedure must be assembled and the .OBJ file linked to
 the BASIC code listed above.


 ; *************************PrintMessage1************************


 ; Prints a string passed by BASIC.





 .model  medium, basic; Use same model as BASIC.


 .code





 ; Define procedure with one-word argument.


 PrintMessage1 procuses ds, descriptor





 ; Define external (BASIC library) procedures.


 extrnStringAddress. proc far


 extrnStringLength. proc far





 mov ax, descriptor ; Find length of string.


 pushax


 callStringLength


 pushax; Save length on stack.





 mov ax, descriptor ; Go find out the


 pushax; address of the string


 CALLStringAddress; data.





 mov ds, dx  ; Address of string.


 mov dx, ax


 mov bx, 01  ; Handle of printer.


 pop cx; Length of string.


 mov ah, 40h ; Have DOS print it.


 int 21h


 ret


 PrintMessage1 endp





 end