DosGetShrSeg

Description

This call accesses a shared memory segment previously allocated by another process.

Syntax

 DosGetShrSeg

    (Name, Selector)

Parameters

Name (PSZ) - input

Address of the name string associated with the shared memory segment to be accessed. The name is an ASCIIZ string in the format of an OS/2 filename in a subdirectory called \SHAREMEM\, for example, \SHAREMEM\PUBLIC.DAT.

Selector (PSEL) - output

Address of the selector for the shared memory segment.

Return Code

rc (USHORT) - return

Return code descriptions are:

• 0 NO_ERROR
• 2 ERROR_FILE_NOT_FOUND
• 4 ERROR_TOO_MANY_OPEN_FILES
• 123 ERROR_INVALID_NAME

Remarks

DosGetShrSeg provides access to a named shared segment allocated by another process with DosAllocShrSeg. The selector returned by DosGetShrSeg is the same as the one returned by the DosAllocShrSeg call.

A usage count is maintained for a named shared segment. Issuing DosGetShrSeg increments the count, and issuing DosFreeSeg decrements the count. When the usage count equals zero, the named shared segment is deallocated. Once the segment has been deallocated, it must be reinitialized by a call to DosAllocShrSeg.

To access shared memory that is allocated by another process with DosAllocSeg and DosAllocHuge requests, a process issues DosGetSeg.

Example Code

C Binding

#define INCL_DOSMEMMGR

USHORT  rc = DosGetShrSeg(Name, Selector);

PSZ              Name;          /* Name string */
PSEL             Selector;      /* Selector of shared segment */

USHORT           rc;            /* return code /*

MASM Binding

EXTRN  DosGetShrSeg:FAR
INCL_DOSMEMMGR      EQU 1

PUSH@  ASCIIZ  Name          ;Name string
PUSH@  WORD    Selector      ;Selector of shared segment (returned)
CALL   DosGetShrSeg

Returns WORD