debian man page for ost_threadfile

Query: ost_threadfile

OS: debian

Section: 3

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ost::ThreadFile(3)					     Library Functions Manual						ost::ThreadFile(3)

NAME
ost::ThreadFile - This class defines a database I/O file service that can be shared by multiple threads.
SYNOPSIS
#include <file.h> Inherits ost::RandomFile. Public Member Functions ThreadFile (const char *path) Open or create a new database file. virtual ~ThreadFile () Close and finish a database file. Error restart (void) Restart an existing database; close and re-open. Error fetch (caddr_t address=NULL, ccxx_size_t length=0, off_t position=-1) Fetch a portion of the file into physical memory. Error update (caddr_t address=NULL, ccxx_size_t length=0, off_t position=-1) Update a portion of a file from physical memory. Error append (caddr_t address=NULL, ccxx_size_t length=0) Add new data to the end of the file. off_t getPosition (void) Fetch the current file position marker for this thread. bool operator++ (void) bool operator-- (void) Additional Inherited Members Detailed Description This class defines a database I/O file service that can be shared by multiple threads. All threads access a global copy of the database object, and mutex locks can be used to preserve transaction integrety. pread/pwrite calls can be used for optimized I/O when supported. ThreadFile is meant for use by a threaded database server where multiple threads may each perform semi-independent operations on a given database table stored on disk. A special 'fcb' structure is used to hold file 'state', and pread/pwrite is used whenever possible for optimized I/O. On systems that do not offer pwread/pwrite, a Mutex lock is used to protect concurrent lseek and read/write operations. ThreadFile managed databases are assumed to be used only by the local server and through a single file descriptor. Author: David Sugar dyfet@ostel.com This class defines a database I/O file service that can be shared by multiple threads. Constructor &; Destructor Documentation ost::ThreadFile::ThreadFile (const char *path) Open or create a new database file. You should also use Initial. Parameters: path pathname of database to open. virtual ost::ThreadFile::~ThreadFile () [virtual] Close and finish a database file. Member Function Documentation Error ost::ThreadFile::append (caddr_taddress = NULL, ccxx_size_tlength = 0) Add new data to the end of the file. Parameters: address address to use, or NULL if same as last I/O. length length to use, or 0 if same as last I/O. Error ost::ThreadFile::fetch (caddr_taddress = NULL, ccxx_size_tlength = 0, off_tposition = -1) Fetch a portion of the file into physical memory. This can use state information to fetch the current record multiple times. Returns: errSuccess on success. Parameters: address address to use, or NULL if same as last I/O. length length to use, or 0 if same as last I/O. position file position to use -1 if same as last I/O. off_t ost::ThreadFile::getPosition (void) Fetch the current file position marker for this thread. Returns: file position offset. bool ost::ThreadFile::operator++ (void) bool ost::ThreadFile::operator-- (void) Error ost::ThreadFile::restart (void) [virtual] Restart an existing database; close and re-open. Returns: errSuccess if successful. Reimplemented from ost::RandomFile. Error ost::ThreadFile::update (caddr_taddress = NULL, ccxx_size_tlength = 0, off_tposition = -1) Update a portion of a file from physical memory. This can use state information to commit the last read record. Returns: errSuccess on success. Parameters: address address to use, or NULL if same as last I/O. length length to use, or 0 if same as last I/O. position file position to use or -1 if same as last I/O. Author Generated automatically by Doxygen for GNU CommonC++ from the source code. GNU CommonC++ Sat Jun 23 2012 ost::ThreadFile(3)
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