DosAllocShrSeg

This call allocates a named shared memory segment to a process.

Syntax

DosAllocShrSeg (Size, Name, Selector)

Parameters

Size (USHORT) - input : Number of bytes requested. The value specified must be less than or equal to 65535. A value of 0 indicates 65536 bytes.
Name (PSZ) - input : Address of the name string associated with the shared memory segment to be allocated. Name specifies the symbolic name for the shared memory segment. The name string is an ASCIIZ string in the format of an OS/2 file name in a subdirectory called \SHAREMEM\. The name string must include the prefix \SHAREMEM\. For example \SHAREMEM\name.
Selector (PSEL) - output : Address where the selector of the allocated segment is returned.

Return Code

rc (USHORT) - return:Return code descriptions are:

0 NO_ERROR
8 ERROR_NOT_ENOUGH_MEMORY
123 ERROR_INVALID_NAME
183 ERROR_ALREADY_EXISTS

Remarks

DosAllocShrSeg allocates a named segment of up to 64KB in size, which is movable and swappable. The segment can be shared by any process that knows the name of the segment.

To access the shared segment, another process issues DosGetShrSeg, specifying the segment name. The selector returned by DosGetShrSeg is the same as the one returned by DosAllocShrSeg.

The maximum number of segments a process can define with DosAllocShrSeg or access with DosGetShrSeg is 256.

;Note: This request may be issued from privilege level 2. However, the segment is allocated as a privilege level 3 segment.

Bindings

C

#define INCL_DOSMEMMGR
 
USHORT  rc = DosAllocShrSeg(Size, Name, Selector);
 
USHORT  Size;          /* Number of bytes requested */
PSZ     Name;          /* Name string */
PSEL    Selector;      /* Selector allocated (returned) */
 
USHORT  rc;            /* return code */

MASM

EXTRN  DosAllocShrSeg:FAR
INCL_DOSMEMMGR      EQU 1
 
PUSH   WORD    Size          ;Number of bytes requested
PUSH@  ASCIIZ  Name          ;Name string
PUSH@  WORD    Selector      ;Selector allocated (returned)
CALL   DosAllocShrSeg
 
Returns WORD

Example Code

This example requests a segment of memory with 27 bytes named “stock.dat”.

#define INCL_DOSMEMMGR
 
#define NUMBER_OF_BYTES 27
#define NAME_SEG "\\SHAREMEM\\stock.dat"
 
SEL    Selector;
USHORT rc;
 
   rc = DosAllocShrSeg(NUMBER_OF_BYTES,   /* # of bytes requested */
                       NAME_SEG,          /* Name string */
                       &Selector);        /* Selector allocated */

Family API
DOS	Process Manager	DosBeep DosExit DosSleep DosExecPgm
	File Manager	DosChDir DosChgFilePtr DosClose DosDelete DosDupHandle DosMkDir DosMove DosQCurDir DosQCurDisk DosSetFileMode DosOpen DosQFileInfo DosRead DosQFileMode DosQFSInfo DosQVerify DosRmDir DosSelectDisk DosFindClose DosFindFirst DosFindNext DosSetFileInfo DosSetVerify DosWrite DosFileLocks DosSetFHandState DosNewSize DosBufReset DosQFHandState DosSetFSinfo
	Memory Manager	DosFreeSeg DosSubAlloc DosSubFree DosSubSet DosAllocHuge DosAllocSeg DosReallocHuge DosReallocSeg DosGetHugeShift DosCreateCSAlias
	NLS	DosCaseMap DosGetCtryInfo DosGetDBCSEv DosSetCtryCode DosGetCollate DosGetMessage DosInsMessage DosPutMessage
	Date and Time	DosSetDateTime DosGetDateTime
	Devices	DosDevConfig DosDevIOCtl DosDevIOCtl2
	Signals	DosHoldSignal DosSetSigHandler
	Misc	BadDynLink DosGetEnv DosGetMachineMode DosGetVersion DosError DosErrClass DosSetVec
KBD		KbdCharIn KbdFlushBuffer KbdGetStatus KbdSetStatus KbdStringIn KbdPeek
VIO		VioGetBuf VioGetConfig VioGetCurPos VioGetCurType VioGetPhysBuf VioReadCellStr VioReadCharStr VioScrollUp VioScrollDn VioScrollLf VioScrollRt VioScrUnLock VioSetCurPos VioSetCurType VioSetMode VioGetMode VioShowBuf VioWrtCellStr VioWrtCharStr VioWrtCharStrAtt VioWrtNAttr VioWrtNCell VioWrtNChar VioWrtTTY VioScrLock VioPopUp
Tools		BIND
Modules		DOSCALLS.DLL VIOCALLS.DLL KBDCALLS.DLL MSG.DLL
Libraries		API.LIB OS2386.LIB FAPI.LIB DOSCALLS.LIB SUBCALLS.LIB

2018/08/25 15:05 · prokushev · 0 Comments

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