Provided by: libsc-doc_2.3.1-21_all bug

NAME

       sc::ShmMemoryGrp - The ShmMemoryGrp concrete class provides an implementation of
       MsgMemoryGrp.

SYNOPSIS

       #include <memshm.h>

       Inherits sc::MsgMemoryGrp.

   Public Member Functions
       ShmMemoryGrp (const Ref< MessageGrp > &msg)
       ShmMemoryGrp (const Ref< KeyVal > &)
       void set_localsize (size_t)
           Set the size of locally held memory.
       void * localdata ()
           Returns a pointer to the local data.
       void * obtain_readwrite (distsize_t offset, int size)
           Only one thread can have an unreleased obtain_readwrite at a time.
       void * obtain_readonly (distsize_t offset, int size)
           This gives read access to the memory location. No locking is done.
       void * obtain_writeonly (distsize_t offset, int size)
           This gives write access to the memory location. No locking is done.
       void release_readonly (void *data, distsize_t offset, int size)
           This is called when read access is no longer needed.
       void release_writeonly (void *data, distsize_t offset, int size)
           This is called when write access is no longer needed.
       void release_readwrite (void *data, distsize_t offset, int size)
           This is called when read/write access is no longer needed.
       void print (std::ostream &o=ExEnv::out0()) const
           Prints out information about the object.

   Additional Inherited Members

Detailed Description

       The ShmMemoryGrp concrete class provides an implementation of MsgMemoryGrp.

       It uses SYSV IPC to provided shared memory in a system that provide shared memory in
       hardware. It is very fast and reliable.

Member Function Documentation

   void* sc::ShmMemoryGrp::obtain_readwrite (distsize_t offset, int size) [virtual]
       Only one thread can have an unreleased obtain_readwrite at a time. The actual memory
       region locked can be larger than that requested. If the memory region is already locked
       this will block. For this reason, data should be held as read/write for as short a time as
       possible.

       Implements sc::MemoryGrp.

   void sc::ShmMemoryGrp::release_readwrite (void * data, distsize_t offset, int size) [virtual]
       This is called when read/write access is no longer needed. The memory will be unlocked.

       Implements sc::MemoryGrp.

   void sc::ShmMemoryGrp::set_localsize (size_t) [virtual]
       Set the size of locally held memory. When memory is accessed using a global offset
       counting starts at node 0 and proceeds up to node n() - 1.

       Reimplemented from sc::MsgMemoryGrp.

Author

       Generated automatically by Doxygen for MPQC from the source code.