Q(uick)BASIC Function: SSEGADD

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SSEGADD

A function that returns the far address of stringvariable& (both segment and offset)

Worth knowing

Useful and cross-version information about the programming environments of QBasic and QuickBasic.

Syntax

SSEGADD(stringvariable$)

Description/Parameter(s)

stringvariable$	The string variable for which you want to find an address. It can be a simple string variable or a single element of a string array. You cannot use fixed-length string arguments.
SSEGADD returns the far address of stringvariable& (both segment and offset).

This function is typically used in mixed-language programming to obtain far addresses before passing far strings to procedures written in other languages.

Usage Notes

The SSEGADD function combines the segment and offset information into one long integer (4 bytes).
SSEGADD usually is used with far strings but can also be used with strings stored in DGROUP.
The offset of a string can be found with the SADD function; the segment of a string can be found with the SSEG function.

Example

This example uses the SSEGADD function to obtain the BASIC string address of a string used by a C procedure. The BASIC program calls the printmessage C procedure which, in turn, calls BASIC to obtain the string address.
Note: To run this program, you must first compile the C procedure (shown below in remarks) and incorporate it in a Quick library or link it to the compiled BASIC program.

DEFINT A-Z
DECLARE SUB printmessage CDECL (BYVAL farstring AS LONG)
'Create the message as an ASCIIZ string, as required by the C printf
'function.
a$ = "This is a short example of a message" + CHR$(0)
'Call the C procedure with pointers.
CALL printmessage(SSEGADD(a$))
 
 
'/* C Routine printmessage */
'/* Prints a BASIC far string on the screen.*/
'
'#include <stdio.h>
'
'/* Define a procedure which inputs a string far pointer */
'void  printmessage (char far *farpointer)
'   {
'   /* print the string addressed by the far pointer */
'   printf( "%s
", farpointer);
'   }
'