.TH "ost::ThreadFile" 3 "Sun Dec 27 2020" "GNU CommonC++" \" -*- nroff -*-
.ad l
.nh
.SH NAME
ost::ThreadFile \- This class defines a database I/O file service that can be shared by multiple threads\&.  

.SH SYNOPSIS
.br
.PP
.PP
\fC#include <file\&.h>\fP
.PP
Inherits \fBost::RandomFile\fP\&.
.SS "Public Member Functions"

.in +1c
.ti -1c
.RI "\fBThreadFile\fP (const char *path)"
.br
.RI "Open or create a new database file\&. "
.ti -1c
.RI "virtual \fB~ThreadFile\fP ()"
.br
.RI "Close and finish a database file\&. "
.ti -1c
.RI "\fBError\fP \fBrestart\fP (void)"
.br
.RI "Restart an existing database; close and re-open\&. "
.ti -1c
.RI "\fBError\fP \fBfetch\fP (caddr_t address=NULL, \fBccxx_size_t\fP length=0, off_t position=\-1)"
.br
.RI "Fetch a portion of the file into physical memory\&. "
.ti -1c
.RI "\fBError\fP \fBupdate\fP (caddr_t address=NULL, \fBccxx_size_t\fP length=0, off_t position=\-1)"
.br
.RI "Update a portion of a file from physical memory\&. "
.ti -1c
.RI "\fBError\fP \fBappend\fP (caddr_t address=NULL, \fBccxx_size_t\fP length=0)"
.br
.RI "Add new data to the end of the file\&. "
.ti -1c
.RI "off_t \fBgetPosition\fP (void)"
.br
.RI "Fetch the current file position marker for this thread\&. "
.ti -1c
.RI "bool \fBoperator++\fP (void)"
.br
.ti -1c
.RI "bool \fBoperator\-\-\fP (void)"
.br
.in -1c
.SS "Additional Inherited Members"
.SH "Detailed Description"
.PP 
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\&.
.PP
\fBThreadFile\fP 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 \fBMutex\fP lock is used to protect concurrent lseek and read/write operations\&. \fBThreadFile\fP managed databases are assumed to be used only by the local server and through a single file descriptor\&.
.PP
\fBAuthor\fP
.RS 4
David Sugar dyfet@ostel.com
.RE
.PP
This class defines a database I/O file service that can be shared by multiple threads\&. 
.SH "Constructor & Destructor Documentation"
.PP 
.SS "ost::ThreadFile::ThreadFile (const char * path)"

.PP
Open or create a new database file\&. You should also use Initial\&.
.PP
\fBParameters\fP
.RS 4
\fIpath\fP pathname of database to open\&. 
.RE
.PP

.SS "virtual ost::ThreadFile::~ThreadFile ()\fC [virtual]\fP"

.PP
Close and finish a database file\&. 
.SH "Member Function Documentation"
.PP 
.SS "\fBError\fP ost::ThreadFile::append (caddr_t address = \fCNULL\fP, \fBccxx_size_t\fP length = \fC0\fP)"

.PP
Add new data to the end of the file\&. 
.PP
\fBParameters\fP
.RS 4
\fIaddress\fP address to use, or NULL if same as last I/O\&. 
.br
\fIlength\fP length to use, or 0 if same as last I/O\&. 
.RE
.PP

.SS "\fBError\fP ost::ThreadFile::fetch (caddr_t address = \fCNULL\fP, \fBccxx_size_t\fP length = \fC0\fP, off_t position = \fC\-1\fP)"

.PP
Fetch a portion of the file into physical memory\&. This can use state information to fetch the current record multiple times\&.
.PP
\fBReturns\fP
.RS 4
errSuccess on success\&. 
.RE
.PP
\fBParameters\fP
.RS 4
\fIaddress\fP address to use, or NULL if same as last I/O\&. 
.br
\fIlength\fP length to use, or 0 if same as last I/O\&. 
.br
\fIposition\fP file position to use -1 if same as last I/O\&. 
.RE
.PP

.SS "off_t ost::ThreadFile::getPosition (void)"

.PP
Fetch the current file position marker for this thread\&. 
.PP
\fBReturns\fP
.RS 4
file position offset\&. 
.RE
.PP

.SS "bool ost::ThreadFile::operator++ (void)"

.SS "bool ost::ThreadFile::operator\-\- (void)"

.SS "\fBError\fP ost::ThreadFile::restart (void)\fC [virtual]\fP"

.PP
Restart an existing database; close and re-open\&. 
.PP
\fBReturns\fP
.RS 4
errSuccess if successful\&. 
.RE
.PP

.PP
Reimplemented from \fBost::RandomFile\fP\&.
.SS "\fBError\fP ost::ThreadFile::update (caddr_t address = \fCNULL\fP, \fBccxx_size_t\fP length = \fC0\fP, off_t position = \fC\-1\fP)"

.PP
Update a portion of a file from physical memory\&. This can use state information to commit the last read record\&.
.PP
\fBReturns\fP
.RS 4
errSuccess on success\&. 
.RE
.PP
\fBParameters\fP
.RS 4
\fIaddress\fP address to use, or NULL if same as last I/O\&. 
.br
\fIlength\fP length to use, or 0 if same as last I/O\&. 
.br
\fIposition\fP file position to use or -1 if same as last I/O\&. 
.RE
.PP


.SH "Author"
.PP 
Generated automatically by Doxygen for GNU CommonC++ from the source code\&.