ACE_DLL_Handle Class Reference

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

#include <DLL_Manager.h>

List of all members.

Public Member Functions
	ACE_DLL_Handle (void)
	Default construtor.
	~ACE_DLL_Handle (void)
	Destructor.
const ACE_TCHAR *	dll_name () const
	Returns the name of the shared library (without prefixes or suffixes).
int	open (const ACE_TCHAR *dll_name, int open_mode, ACE_SHLIB_HANDLE handle)
int	close (int unload=0)
sig_atomic_t	refcount (void) const
	Return the current refcount.
void *	symbol (const ACE_TCHAR *symbol_name, int ignore_errors=0)
ACE_SHLIB_HANDLE	get_handle (int become_owner=0)
Private Member Functions
auto_ptr< ACE_TString >	error (void)
void	get_dll_names (const ACE_TCHAR *dll_name, ACE_Array< ACE_TString > &try_names)
	ACE_DLL_Handle (const ACE_DLL_Handle &)
void	operator= (const ACE_DLL_Handle &)
Private Attributes
sig_atomic_t	refcount_
ACE_TCHAR *	dll_name_
	Name of the shared library.
ACE_SHLIB_HANDLE	handle_
	Handle to the actual library loaded by the OS.
Static Private Attributes
static sig_atomic_t	open_called_ = 0

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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. It is refcounted and managed by ACE_DLL_Manager, so there will only be a single instance of this class for each dll loaded, no matter how many instances of ACE_DLL an application has open. Operations <open>, <close>, and <symbol> have been implemented to help opening/closing and extracting symbol information from a DLL, respectively.

Most of this class came from the original ACE_DLL class. ACE_DLL is now just an interface that passed all it's calls either directly or via ACE_DLL_Manager to this class for execution.

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Constructor & Destructor Documentation

ACE_DLL_Handle::ACE_DLL_Handle

(

void

)

Default construtor.

ACE_DLL_Handle::~ACE_DLL_Handle

(

void

)

Destructor.

ACE_DLL_Handle::ACE_DLL_Handle

(

const ACE_DLL_Handle &

)

[private]

---

Member Function Documentation

const ACE_TCHAR * ACE_DLL_Handle::dll_name

(

void

)

const

Returns the name of the shared library (without prefixes or suffixes).

int ACE_DLL_Handle::open	(	const ACE_TCHAR *	dll_name,
		int	open_mode,
		ACE_SHLIB_HANDLE	handle
	)

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. Returns -1 on failure and 0 on success.

int ACE_DLL_Handle::close

(

int

unload = 0

)

Call to close the DLL object. If unload = 0, it only decrements the refcount, but if unload = 1, then it will actually unload the library when the refcount == 0;

sig_atomic_t ACE_DLL_Handle::refcount

(

void

)

const

Return the current refcount.

void * ACE_DLL_Handle::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. Set the ignore_errors flag to supress logging errors if symbol_name isn't found. This is nice if you just want to probe a dll to see what's available, since missing functions in that case aren't really errors.

ACE_SHLIB_HANDLE ACE_DLL_Handle::get_handle

(

int

become_owner = 0

)

Return the handle to the caller. If become_owner is non-0 then caller assumes ownership of the handle so we decrement the retcount.

auto_ptr< ACE_TString > ACE_DLL_Handle::error

(

void

)

[private]

Returns a pointer to a string explaining why <symbol> or <open> failed. This is used internal to print out the error to the log, but since this object is shared, we can't store or return the error to the caller.

void ACE_DLL_Handle::get_dll_names	(	const ACE_TCHAR *	dll_name,
		ACE_Array< ACE_TString > &	try_names
	)			[private]

void ACE_DLL_Handle::operator=

(

const ACE_DLL_Handle &

)

[private]

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Member Data Documentation

sig_atomic_t ACE_DLL_Handle::refcount_ [private]

ACE_TCHAR* ACE_DLL_Handle::dll_name_ [private]

Name of the shared library.

ACE_SHLIB_HANDLE ACE_DLL_Handle::handle_ [private]

Handle to the actual library loaded by the OS.

ACE_BEGIN_VERSIONED_NAMESPACE_DECL sig_atomic_t ACE_DLL_Handle::open_called_ = 0 [static, private]

Keeps track of whether or not open() has ever been called. This helps get around problem on Linux, and perhaps other OS's, that seg-fault if dlerror() is called before the ld library has been initialized by a call to dlopen().

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

• DLL_Manager.h
• DLL_Manager.cpp