pqxx::largeobjectaccess Class Reference

Accessor for large object's contents. More...

#include <largeobject.hxx>

Inheritance diagram for pqxx::largeobjectaccess:

List of all members.

Public Types
typedef long	off_type
typedef size_type	pos_type
typedef PGSTD::ios::openmode	openmode
	Open mode: in, out (can be combined with the "or" operator).
typedef PGSTD::ios::seekdir	seekdir
	Seek direction: beg, cur, end.
typedef long	size_type
Public Member Functions
	largeobjectaccess (dbtransaction &T, openmode mode=PGSTD::ios::in|PGSTD::ios::out)
	Create new large object and open it.
	largeobjectaccess (dbtransaction &T, oid O, openmode mode=PGSTD::ios::in|PGSTD::ios::out)
	Open large object with given oid.
	largeobjectaccess (dbtransaction &T, largeobject O, openmode mode=PGSTD::ios::in|PGSTD::ios::out)
	Open given large object.
	largeobjectaccess (dbtransaction &T, const PGSTD::string &File, openmode mode=PGSTD::ios::in|PGSTD::ios::out)
	Import large object from a local file and open it.
	~largeobjectaccess () throw ()
void	to_file (const PGSTD::string &File) const
	Export large object's contents to a local file.
void	write (const char Buf[], size_type Len)
	Write data to large object.
void	write (const PGSTD::string &Buf)
	Write string to large object.
size_type	read (char Buf[], size_type Len)
	Read data from large object.
size_type	seek (size_type dest, seekdir dir)
	Seek in large object's data stream.
pos_type	cseek (off_type dest, seekdir dir) throw ()
	Seek in large object's data stream.
off_type	cwrite (const char Buf[], size_type Len) throw ()
	Write to large object's data stream.
off_type	cread (char Buf[], size_type Len) throw ()
	Read from large object's data stream.
void	process_notice (const PGSTD::string &) throw ()
	Issue message to transaction's notice processor.
oid	id () const throw ()
	Object identifier.
void	to_file (dbtransaction &T, const PGSTD::string &File) const
	Export large object's contents to a local file.
void	remove (dbtransaction &T) const
	Delete large object from database.

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Detailed Description

Accessor for large object's contents.

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Member Typedef Documentation

typedef long pqxx::largeobjectaccess::off_type

typedef PGSTD::ios::openmode pqxx::largeobjectaccess::openmode

Open mode: in, out (can be combined with the "or" operator). According to the C++ standard, these should be in std::ios_base. We take them from std::ios instead, which should be safe because it inherits the same definition, to accommodate gcc 2.95 & 2.96.

typedef size_type pqxx::largeobjectaccess::pos_type

typedef PGSTD::ios::seekdir pqxx::largeobjectaccess::seekdir

Seek direction: beg, cur, end. According to the C++ standard, these should be in std::ios_base. We take them from std::ios instead, which should be safe because it inherits the same definition, to accommodate gcc 2.95 & 2.96.

typedef long pqxx::largeobject::size_type

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Constructor & Destructor Documentation

pqxx::largeobjectaccess::largeobjectaccess (  dbtransaction &  T, openmode  mode = PGSTD::ios::in|PGSTD::ios::out )  [explicit]

Create new large object and open it. Parameters: T  Backend transaction in which the object is to be created mode  Access mode, defaults to ios_base::in | ios_base::out

pqxx::largeobjectaccess::largeobjectaccess (  dbtransaction &  T, oid  O, openmode  mode = PGSTD::ios::in|PGSTD::ios::out )

Open large object with given oid. Convert combination of a transaction and object identifier into a large object identity. Does not affect the database. Parameters: T  Transaction in which the object is to be accessed O  Object identifier for the given object mode  Access mode, defaults to ios_base::in | ios_base::out

pqxx::largeobjectaccess::largeobjectaccess (  dbtransaction &  T, largeobject  O, openmode  mode = PGSTD::ios::in|PGSTD::ios::out )

Open given large object. Open a large object with the given identity for reading and/or writing Parameters: T  Transaction in which the object is to be accessed O  Identity for the large object to be accessed mode  Access mode, defaults to ios_base::in | ios_base::out

pqxx::largeobjectaccess::largeobjectaccess (  dbtransaction &  T, const PGSTD::string &  File, openmode  mode = PGSTD::ios::in|PGSTD::ios::out )

Import large object from a local file and open it. Creates a large object containing the data found in the given file. Parameters: T  Backend transaction in which the large object is to be created File  A filename on the client program's filesystem mode  Access mode, defaults to ios_base::in | ios_base::out

pqxx::largeobjectaccess::~largeobjectaccess (   )  throw ()

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Member Function Documentation

long pqxx::largeobjectaccess::cread (  char  Buf[], size_type  Len )  throw ()

Read from large object's data stream. Does not throw exception in case of error; inspect return value and errno instead. Parameters: Buf  Area where incoming bytes should be stored Len  Number of bytes to read Returns: Number of bytes actually read, or -1 if an error occurred.

long pqxx::largeobjectaccess::cseek (  off_type  dest, seekdir  dir )  throw ()

Seek in large object's data stream. Does not throw exception in case of error; inspect return value and errno instead. Parameters: dest  Offset to go to dir  Origin to which dest is relative: ios_base::beg (from beginning of the object), ios_base::cur (from current access position), or ios_base;:end (from end of object) Returns: New position in large object, or -1 if an error occurred.

long pqxx::largeobjectaccess::cwrite (  const char  Buf[], size_type  Len )  throw ()

Write to large object's data stream. Does not throw exception in case of error; inspect return value and errno instead. Parameters: Buf  Data to write Len  Number of bytes to write Returns: Number of bytes actually written, or -1 if an error occurred.

oid pqxx::largeobject::id (   )  const throw ()

Object identifier. The number returned by this function uniquely identifies the large object in the context of the database we're connected to.

void pqxx::largeobjectaccess::process_notice (  const PGSTD::string &   )  throw ()

Issue message to transaction's notice processor.

pqxx::largeobjectaccess::size_type pqxx::largeobjectaccess::read (  char  Buf[], size_type  Len )

Read data from large object. Throws an exception if an error occurs while reading. Parameters: Buf  Location to store the read data in Len  Number of bytes to try and read Returns: Number of bytes read, which may be less than the number requested if the end of the large object is reached

void pqxx::largeobject::remove (  dbtransaction &  T  )  const

Delete large object from database. Unlike its low-level equivalent cunlink, this will throw an exception if deletion fails. Parameters: T  Transaction in which the object is to be deleted

pqxx::largeobjectaccess::size_type pqxx::largeobjectaccess::seek (  size_type  dest, seekdir  dir )

Seek in large object's data stream. Throws an exception if an error occurs. Returns: The new position in the large object

void pqxx::largeobject::to_file (  dbtransaction &  T, const PGSTD::string &  File )  const

Export large object's contents to a local file. Writes the data stored in the large object to the given file. Parameters: T  Transaction in which the object is to be accessed File  A filename on the client's filesystem

void pqxx::largeobjectaccess::to_file (  const PGSTD::string &  File  )  const

Export large object's contents to a local file. Writes the data stored in the large object to the given file. Parameters: File  A filename on the client's filesystem

void pqxx::largeobjectaccess::write (  const PGSTD::string &  Buf  )

Write string to large object. If not all bytes could be written, an exception is thrown. Parameters: Buf  Data to write; no terminating zero is written

void pqxx::largeobjectaccess::write (  const char  Buf[], size_type  Len )

Write data to large object. If not all bytes could be written, an exception is thrown. Parameters: Buf  Data to write Len  Number of bytes from Buf to write

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The documentation for this class was generated from the following files:

• largeobject.hxx
• largeobject.cxx

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