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ost::ThreadFile

ost::ThreadFile

Section: C Library Functions (3) Updated: 16 Feb 2010
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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 (char *address=NULL, ccxx_size_t length=0, off_t position=-1)
Fetch a portion of the file into physical memory.
Error update (char *address=NULL, ccxx_size_t length=0, off_t position=-1)
Update a portion of a file from physical memory.
Error append (char *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)
 

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 (char * address = NULL, ccxx_size_t length = 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 (char * address = NULL, ccxx_size_t length = 0, off_t position = -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 (char * address = NULL, ccxx_size_t length = 0, off_t position = -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.


 

Index

NAME
SYNOPSIS
Public Member Functions
Detailed Description
Constructor & Destructor Documentation
ost::ThreadFile::ThreadFile (const char * path)
virtual ost::ThreadFile::~ThreadFile () [virtual]
Member Function Documentation
Error ost::ThreadFile::append (char * address = NULL, ccxx_size_t length = 0)
Error ost::ThreadFile::fetch (char * address = NULL, ccxx_size_t length = 0, off_t position = -1)
off_t ost::ThreadFile::getPosition (void)
bool ost::ThreadFile::operator++ (void)
bool ost::ThreadFile::operator-- (void)
Error ost::ThreadFile::restart (void) [virtual]
Error ost::ThreadFile::update (char * address = NULL, ccxx_size_t length = 0, off_t position = -1)
Author

This document was created by man2html, using the manual pages.
Time: 21:51:52 GMT, April 16, 2011