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ACE_DLL Class Reference

Provides an abstract interface for handling various DLL operations. More...

#include <DLL.h>

Collaboration diagram for ACE_DLL:

[legend]List of all members.

Public Methods
	ACE_DLL (int close_on_destruction=1)
	ACE_DLL (const ACE_TCHAR *dll_name, int open_mode=ACE_DEFAULT_SHLIB_MODE, int close_on_destruction=1)
	ACE_DLL (const ACE_DLL &)
	Copy constructor.
int	open (const ACE_TCHAR *dll_name, int open_mode=ACE_DEFAULT_SHLIB_MODE, int close_on_destruction=1)
int	close (void)
	Call to close the DLL object.
	~ACE_DLL (void)
void *	symbol (const ACE_TCHAR *symbol_name, int ignore_errors=0)
ACE_TCHAR *	error (void) const
ACE_SHLIB_HANDLE	get_handle (int become_owner=0) const
int	set_handle (ACE_SHLIB_HANDLE handle, int close_on_destruction=1)
	Set the handle for the DLL object. By default, the close().
Private Methods
int	open_i (const ACE_TCHAR *dll_name, int open_mode=ACE_DEFAULT_SHLIB_MODE, int close_on_destruction=1, ACE_SHLIB_HANDLE handle=0)
void	operator= (const ACE_DLL &)
Private Attributes
int	open_mode_
	Open mode.
ACE_TCHAR *	dll_name_
int	close_on_destruction_
ACE_DLL_Handle *	dll_handle_
int	error_
	Flag to record if the last operation had an error.

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Detailed Description

Provides an abstract interface for handling various DLL operations.

This class is an wrapper over the various methods for utilizing a dynamically linked library (DLL), which is called a shared library on some platforms. Operations open(), close(), and symbol() have been implemented to help opening/closing and extracting symbol information from a DLL, respectively.

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Constructor & Destructor Documentation

ACE_DLL::ACE_DLL (  int    close_on_destruction = 1 )  [explicit]

Default constructor. By default, the close() operation on the object will be invoked before it is destroyed.

ACE_DLL::ACE_DLL (  const ACE_TCHAR *    dll_name, int    open_mode = ACE_DEFAULT_SHLIB_MODE, int    close_on_destruction = 1 )  [explicit]

This constructor opens and dynamically links dll_name. The default mode is <RTLD_LAZY>, which loads identifier symbols but not the symbols for functions, which are loaded dynamically on-demand. Other supported modes include: <RTLD_NOW>, which performs all necessary relocations when dll_name is first loaded and <RTLD_GLOBAL>, which makes symbols available for relocation processing of any other DLLs.

ACE_DLL::ACE_DLL (  const ACE_DLL &    )

Copy constructor.

ACE_DLL::~ACE_DLL (  void    )

Called when the DLL object is destroyed -- invokes close() if the <close_on_destruction> flag is set in the constructor or open() method.

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Member Function Documentation

int ACE_DLL::close (  void    )

Call to close the DLL object.

ACE_TCHAR * ACE_DLL::error (  void    )  const

Returns a pointer to a string explaining that an error occured. You will need to consult the error log for the actual error string returned by the OS.

ACE_SHLIB_HANDLE ACE_DLL::get_handle (  int    become_owner = 0 )  const

Return the handle to the caller. If become_owner is non-0 then caller assumes ownership of the handle and the ACE_DLL object won't call close() when it goes out of scope, even if <close_on_destruction> is set.

int ACE_DLL::open (  const ACE_TCHAR *    dll_name, int    open_mode = ACE_DEFAULT_SHLIB_MODE, int    close_on_destruction = 1 )

This method opens and dynamically links dll_name. The default mode is <RTLD_LAZY>, which loads identifier symbols but not the symbols for functions, which are loaded dynamically on-demand. Other supported modes include: <RTLD_NOW>, which performs all necessary relocations when dll_name>is first loaded and <RTLD_GLOBAL>, which makes symbols available for relocation processing of any other DLLs. Parameters: dll_name  The name of the dll. open_mode  How the dll is opened. close_on_destruction  Close the handle in the destructor. Return values: -1  On failure 0  On success.

int ACE_DLL::open_i (  const ACE_TCHAR *    dll_name, int    open_mode = ACE_DEFAULT_SHLIB_MODE, int    close_on_destruction = 1, ACE_SHLIB_HANDLE    handle = 0 )  [private]

void ACE_DLL::operator= (  const ACE_DLL &    )  [private]

int ACE_DLL::set_handle (  ACE_SHLIB_HANDLE    handle, int    close_on_destruction = 1 )

Set the handle for the DLL object. By default, the close().

void * ACE_DLL::symbol (  const ACE_TCHAR *    symbol_name, int    ignore_errors = 0 )

If symbol_name is in the symbol table of the DLL a pointer to the symbol_name is returned. Otherwise, returns 0. Setting ignore_errors = 1 allows you to probe a dll without generating error messages in the log. Handy for determining the capabilities of a library.

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Member Data Documentation

int ACE_DLL::close_on_destruction_ [private]

This flag keeps track of whether we should close the handle automatically when the destructor runs.

ACE_DLL_Handle* ACE_DLL::dll_handle_ [private]

ACE_TCHAR* ACE_DLL::dll_name_ [private]

Keep track of the name of the loaded dll, so it can be used to remove framework components, singletons that live in the dll, prior to unloading the dll in the close() method.

int ACE_DLL::error_ [private]

Flag to record if the last operation had an error.

int ACE_DLL::open_mode_ [private]

Open mode.

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

• DLL.h
• DLL.cpp

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