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NAMEsc::FileGrp - The FileGrp abstract class provides a way of accessing distributed file in a parallel machine. SYNOPSIS#include <file.h> Inherits sc::DescribedClass. Inherited by sc::ProcFileGrp. Public Member FunctionsFileGrp (const Ref< KeyVal > &)
Public Member Functions inherited from sc::DescribedClass
Public Member Functions inherited from sc::RefCount
Public Member Functions inherited from sc::Identity
Static Public Member Functionsstatic FileGrp * initial_filegrp (int &argc,
char **argv)
Protected Member Functionsvoid obtain_local_lock (size_t start, size_t fence)
Protected Member Functions inherited from sc::RefCount
Protected Attributesint me_
Detailed DescriptionThe FileGrp abstract class provides a way of accessing distributed file in a parallel machine. Several specializations are available. For one processor, ProcFileGrp provides a simple stub implementation. Otherwise, the specializations that should work are MPIIOIFileGrp and MTMPIFileGrp. If a FileGrp is not given to the program, then one will be automatically chosen depending on which MessageGrp is used by default, the type of machine on which the code was compiled, and what options were given at configuration time. Member Function Documentationvirtual void sc::FileGrp::catchup () [virtual]Processes outstanding requests. Some file group implementations don't have access to real shared memory or even active messages. Instead, requests are processed whenever certain file group routines are called. This can cause large latencies and buffer overflows. If this is a problem, then the catchup member can be called to process all outstanding requests. virtual FileGrp * sc::FileGrp::clone () [pure virtual]Clones the given FileGrp. The new FileGrp may need to be initialized additionally. Implemented in sc::ProcFileGrp. static FileGrp * sc::FileGrp::initial_filegrp (int & argc, char ** argv) [static]Create a file group. This routine looks for a -filegrp argument, then the environmental variable FILEGRP, and, finally, the default MessageGrp object to decide which specialization of FileGrp would be appropriate. The argument to -integralgrp should be either string for a ParsedKeyVal constructor or a classname. The default ThreadGrp and MessageGrp objects should be initialized before this is called. References initial_filegrp(). Referenced by initial_filegrp(). virtual void * sc::FileGrp::obtain_readonly (distsize_t offset, int size) [pure virtual]This gives read access to the file location. No locking is done. Implemented in sc::ProcFileGrp. virtual void * sc::FileGrp::obtain_readwrite (distsize_t offset, int size) [pure virtual]Only one thread can have an unreleased obtain_readwrite at a time. The actual file region locked can be larger than that requested. If the file region is already locked this will block. For this reason, data should be held as read/write for as short a time as possible. Implemented in sc::ProcFileGrp. virtual void * sc::FileGrp::obtain_writeonly (distsize_t offset, int size) [pure virtual]This gives write access to the data location. No locking is done. Implemented in sc::ProcFileGrp. virtual void sc::FileGrp::print (std::ostream & o = ExEnv::out0()) const [virtual]Prints out information about the object. Reimplemented from sc::DescribedClass. virtual void sc::FileGrp::release_readonly (void * data, distsize_t offset, int size) [pure virtual]This is called when read access is no longer needed. Implemented in sc::ProcFileGrp. virtual void sc::FileGrp::release_readwrite (void * data, distsize_t offset, int size) [pure virtual]This is called when read/write access is no longer needed. The data will be unlocked. Implemented in sc::ProcFileGrp. virtual void sc::FileGrp::release_writeonly (void * data, distsize_t offset, int size) [pure virtual]This is called when write access is no longer needed. Implemented in sc::ProcFileGrp. virtual void sc::FileGrp::set_localsize (size_t) [pure virtual]Set the size of locally held data. When data is accessed using a global offset counting starts at node 0 and proceeds up to node n() - 1. Implemented in sc::ProcFileGrp. virtual void sc::FileGrp::sync () [pure virtual]Synchronizes all the nodes. Consider using this when the way you you access data changes. Implemented in sc::ProcFileGrp. AuthorGenerated automatically by Doxygen for MPQC from the source code.
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