Table of Contents
Note: This API call is for DOS personality only. Use Family API for portability.
Int 21H, AH=33H, AL=03H
GET CURRENT CPSW STATE
AX = 3303h
DL = current CPSW
this function and AX=3304h were intended to support a proposed code-page switching flag (using the WORD at offset 0Ch in the DOS directory entry for codepage information); however, this function has always been a NOP in public releases of DOS and OS/2. See _DOS_Internals_ Chapter 2 for more information. the released MS-DOS 4.00 IO.SYS has an undocumented CONFIG.SYS directive named CPSW= and that beside others the MS-DOS 4.00 ATTRIB supported a number of undocumented special parameters for "predefined" Extended Attributes (EAs) e.g. ATTRIB filename [(CODEPAGE|CP)[=new_value]]. this function does not use any of the DOS-internal stacks and may thus be called at any time. It is directly dispatched from the INT 21h entry point with interrupts disabled.
Text based on Ralf Brown Interrupt List Release 61