VioGetPhysBuf

Bindings:  C, MASM 

This call gets addressability to the physical display buffer. 

 VioGetPhysBuf     (DisplayBuf, Reserved) 
 

 DisplayBuf(PVIOPHYSBUF) - input/output 
    Address of the data structure that contains the physical display 
    buffer address and length on input and returns the selectors used to 
    address the display buffer. 

    displaybufaddr (PBYTE) 
       Address of the 32 bit start address (selector:offset) of the 
       physical display buffer passed as input. If displaybuflen is 0, 
       then displaybufaddr is the far address of the PhysBuf Block 
       described below. 

    displaybuflen (ULONG) 
       32 bit length of the physical display buffer. If displaybuflen is 
       0, then displaybufaddr is treated as the far address of the PhysBuf 
       Block described below and the Selector List is not present. 

    selectors (SEL) 
       Selector list. 

       Returns the selectors (each of word-length) that address the 
       physical display buffer. The first selector returned in the list, 
       addresses the first 64KB of the physical display buffer or 
       displaybuflen, whichever is smaller.  If displaybuflen is greater 
       than 64KB, the second selector addresses the second 64KB. 

       The last selector returned in the list, addresses the remainder of 
       the display buffer.  The application is responsible for ensuring 
       enough space is reserved for the selector list to accommodate the 
       specified buffer length. 

    PhysBuf Block (PhysBuf) 
       Address of the data structure.  The PhysBuf Block is a variable 
       length data structure.  The first word is the Length of the PhysBuf 
       Block in bytes.  The remaining words of the structure are the 
       selectors that address the physical video buffer.  If Length is 
       specified as 2, the required length of the PhysBuf Block is 
       returned in its place. 

       PhysBuf Block (USHORT) 
          Length of PhysBuf structure in bytes 

       selector (SEL) 
          First selector 

       selector (SEL) 
          Next selector 

       selector (SEL) 
          ... ... 

       selector (SEL) 
          Last selector 

 Reserved (USHORT) - input 
    Reserved word of 0s. 

 rc (USHORT) - return 
    Return code descriptions are: 

    0         NO_ERROR 
    350       ERROR_VIO_PTR 
    429       ERROR_VIO_IN_BG 
    430       ERROR_VIO_ILLEGAL_DURING_POPUP 
    436       ERROR_VIO_INVALID_HANDLE 
    465       ERROR_VIO_DETACHED 
    494       ERROR_VIO_EXTENDED_SG 
 
 Remarks 

 If displaybuflen = 0, VioGetPhysBuf returns a selector that addresses the 
 physical display buffer corresponding to the current mode.  One selector 
 is returned in Selector List. If a VioGetPhysBuf is issued after a 
 VioGetBuf, then all  VioWrtXX calls will on longer be written to the LVB. 
  They will only be written to the physical display buffer. An application 
 uses VioGetPhysBuf to get addressability to the physical display buffer. 
  The selector returned by VioGetPhysBuf may be used only when an 
 application program is executing in the foreground. When an application 
 wants to access the physical display buffer, the application must call 
 VioScrLock.  VioScrLock either waits until the program is running in the 
 foreground or returns a warning when the program is running in the 
 background.  For more information refer to VioScrLock and VioScrUnLock. 

 The buffer range specified for the physical screen buffer must fall 
 between hex 'A0000' and 'BFFFF' inclusive. An application may issue 
 VioGetPhysBuf only when it is running in the foreground.  An application 
 may issue VioGetPhysBuf more than once.