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sc::ShmMemoryGrp(3)                  MPQC                  sc::ShmMemoryGrp(3)

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. Version 2.3.1 Fri Feb 19 2016 sc::ShmMemoryGrp(3)

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