---

ACE_DLL_Handle Class Reference

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

#include <DLL_Manager.h>

List of all members.

Public Methods
	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 Methods
auto_ptr< ACE_TString >	error (void)
	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
sig_atomic_t	open_called_ = 0

---

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.

---

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

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;

const ACE_TCHAR * ACE_DLL_Handle::dll_name (    )

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

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.

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.

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.

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

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.

---

Member Data Documentation

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.

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().

sig_atomic_t ACE_DLL_Handle::refcount_ [private]

---

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

• DLL_Manager.h
• DLL_Manager.cpp

---