mutex Class Reference

SQLite Mutex. More...

Inheritance diagram for mutex:

Public Types
enum	type { fast = SQLITE_MUTEX_FAST , recursive = SQLITE_MUTEX_RECURSIVE }
	Type of mutex to allocate for alloc()

Public Member Functions
void	lock () noexcept
	Lock the mutex.
bool	try_lock () noexcept
	Try to lock the mutex.
void	unlock () noexcept
	Unlock the mutex.
void	operator delete (void *) noexcept
	Operator delete for a fake pointer is no-op.
sqlite3_mutex *	c_ptr () const noexcept
	Access the real underlying SQLite type.

Static Public Member Functions
static std::unique_ptr< mutex >	alloc (type t) noexcept
	Allocate a new mutex.
static mutex *	from (sqlite3_mutex *obj) noexcept
	Create fake pointer from the underlying SQLite one.

Detailed Description

SQLite Mutex.

This is a fake wrapper class for sqlite3_mutex.

Unlike other wrappers in this library the interface of this class does not match the names of SQLite C interface. Instead is made to conform to Lockable C++ standard library concept. This allows you to use it in standard lock related machinery like std::unique_lock or std::lock_guard

In many cases SQLite can return nullptr mutexes due to compile-time or runtime disabling of synchronization. While calling lock(), try_lock() and unlock() on a nullptr this pointer should work fine on all compilers (underlying SQLite functions all support null pointers) it is technically an undefined behavior in C++ (sigh). To avoid this and deal with null mutex pointers safely see lock_adapter class

#include <thinsqlitepp/mutex.hpp>

See also

lock_adapter

Member Function Documentation

alloc()

static std::unique_ptr< mutex > alloc ( type t )

inlinestaticnoexcept

Allocate a new mutex.

Equivalent to sqlite3_mutex_alloc

Note that the interface to this function deliberately disallows access to internal static SQLite mutexes. Accroding to SQLite docs "[s]tatic mutexes are for internal use by SQLite only".

If you do require access to one of the static mutexes you can use from(sqlite3_mutex_alloc(SQLITE_MUTEX_XXX)) manually.

Parameters

t	type of the mutex to allocate

Returns

Newly allocated mutex of nullptr if the SQLite implementation is unable to allocate a mutex (e.g. if it does not support mutexes).

lock()

void lock ( )

inlinenoexcept

Lock the mutex.

Equivalent to sqlite3_mutex_enter

try_lock()

bool try_lock ( )

inlinenoexcept

Try to lock the mutex.

Equivalent to sqlite3_mutex_try

unlock()

void unlock ( )

inlinenoexcept

Unlock the mutex.

Equivalent to sqlite3_mutex_leave