| Index: third_party/sqlite/sqlite-src-3070603/ext/async/sqlite3async.h
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| diff --git a/third_party/sqlite/sqlite-src-3070603/ext/async/sqlite3async.h b/third_party/sqlite/sqlite-src-3070603/ext/async/sqlite3async.h
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| new file mode 100644
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| index 0000000000000000000000000000000000000000..143cdc7703fdaefe44795909b5198332d199c3cb
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| --- /dev/null
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| +++ b/third_party/sqlite/sqlite-src-3070603/ext/async/sqlite3async.h
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| @@ -0,0 +1,223 @@
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| +
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| +#ifndef __SQLITEASYNC_H_
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| +#define __SQLITEASYNC_H_ 1
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| +
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| +/*
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| +** Make sure we can call this stuff from C++.
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| +*/
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| +#ifdef __cplusplus
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| +extern "C" {
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| +#endif
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| +
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| +#define SQLITEASYNC_VFSNAME "sqlite3async"
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| +
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| +/*
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| +** THREAD SAFETY NOTES:
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| +**
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| +** Of the four API functions in this file, the following are not threadsafe:
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| +**
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| +**   sqlite3async_initialize()
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| +**   sqlite3async_shutdown()
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| +**
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| +** Care must be taken that neither of these functions is called while 
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| +** another thread may be calling either any sqlite3async_XXX() function
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| +** or an sqlite3_XXX() API function related to a database handle that
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| +** is using the asynchronous IO VFS.
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| +**
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| +** These functions:
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| +**
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| +**   sqlite3async_run()
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| +**   sqlite3async_control()
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| +**
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| +** are threadsafe. It is quite safe to call either of these functions even
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| +** if another thread may also be calling one of them or an sqlite3_XXX()
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| +** function related to a database handle that uses the asynchronous IO VFS.
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| +*/
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| +
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| +/*
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| +** Initialize the asynchronous IO VFS and register it with SQLite using
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| +** sqlite3_vfs_register(). If the asynchronous VFS is already initialized
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| +** and registered, this function is a no-op. The asynchronous IO VFS
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| +** is registered as "sqlite3async".
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| +**
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| +** The asynchronous IO VFS does not make operating system IO requests 
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| +** directly. Instead, it uses an existing VFS implementation for all
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| +** required file-system operations. If the first parameter to this function
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| +** is NULL, then the current default VFS is used for IO. If it is not
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| +** NULL, then it must be the name of an existing VFS. In other words, the
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| +** first argument to this function is passed to sqlite3_vfs_find() to
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| +** locate the VFS to use for all real IO operations. This VFS is known
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| +** as the "parent VFS".
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| +**
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| +** If the second parameter to this function is non-zero, then the 
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| +** asynchronous IO VFS is registered as the default VFS for all SQLite 
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| +** database connections within the process. Otherwise, the asynchronous IO
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| +** VFS is only used by connections opened using sqlite3_open_v2() that
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| +** specifically request VFS "sqlite3async".
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| +**
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| +** If a parent VFS cannot be located, then SQLITE_ERROR is returned.
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| +** In the unlikely event that operating system specific initialization
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| +** fails (win32 systems create the required critical section and event 
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| +** objects within this function), then SQLITE_ERROR is also returned.
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| +** Finally, if the call to sqlite3_vfs_register() returns an error, then 
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| +** the error code is returned to the user by this function. In all three
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| +** of these cases, intialization has failed and the asynchronous IO VFS
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| +** is not registered with SQLite.
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| +**
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| +** Otherwise, if no error occurs, SQLITE_OK is returned.
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| +*/ 
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| +int sqlite3async_initialize(const char *zParent, int isDefault);
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| +
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| +/*
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| +** This function unregisters the asynchronous IO VFS using 
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| +** sqlite3_vfs_unregister().
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| +**
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| +** On win32 platforms, this function also releases the small number of 
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| +** critical section and event objects created by sqlite3async_initialize().
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| +*/ 
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| +void sqlite3async_shutdown();
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| +
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| +/*
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| +** This function may only be called when the asynchronous IO VFS is 
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| +** installed (after a call to sqlite3async_initialize()). It processes
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| +** zero or more queued write operations before returning. It is expected
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| +** (but not required) that this function will be called by a different 
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| +** thread than those threads that use SQLite. The "background thread"
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| +** that performs IO.
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| +**
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| +** How many queued write operations are performed before returning 
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| +** depends on the global setting configured by passing the SQLITEASYNC_HALT
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| +** verb to sqlite3async_control() (see below for details). By default
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| +** this function never returns - it processes all pending operations and 
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| +** then blocks waiting for new ones.
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| +**
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| +** If multiple simultaneous calls are made to sqlite3async_run() from two
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| +** or more threads, then the calls are serialized internally.
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| +*/
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| +void sqlite3async_run();
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| +
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| +/*
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| +** This function may only be called when the asynchronous IO VFS is 
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| +** installed (after a call to sqlite3async_initialize()). It is used 
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| +** to query or configure various parameters that affect the operation 
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| +** of the asynchronous IO VFS. At present there are three parameters 
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| +** supported:
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| +**
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| +**   * The "halt" parameter, which configures the circumstances under
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| +**     which the sqlite3async_run() parameter is configured.
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| +**
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| +**   * The "delay" parameter. Setting the delay parameter to a non-zero
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| +**     value causes the sqlite3async_run() function to sleep for the
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| +**     configured number of milliseconds between each queued write 
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| +**     operation.
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| +**
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| +**   * The "lockfiles" parameter. This parameter determines whether or 
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| +**     not the asynchronous IO VFS locks the database files it operates
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| +**     on. Disabling file locking can improve throughput.
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| +**
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| +** This function is always passed two arguments. When setting the value
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| +** of a parameter, the first argument must be one of SQLITEASYNC_HALT,
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| +** SQLITEASYNC_DELAY or SQLITEASYNC_LOCKFILES. The second argument must
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| +** be passed the new value for the parameter as type "int".
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| +**
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| +** When querying the current value of a paramter, the first argument must
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| +** be one of SQLITEASYNC_GET_HALT, GET_DELAY or GET_LOCKFILES. The second 
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| +** argument to this function must be of type (int *). The current value
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| +** of the queried parameter is copied to the memory pointed to by the
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| +** second argument. For example:
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| +**
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| +**   int eCurrentHalt;
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| +**   int eNewHalt = SQLITEASYNC_HALT_IDLE;
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| +**
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| +**   sqlite3async_control(SQLITEASYNC_HALT, eNewHalt);
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| +**   sqlite3async_control(SQLITEASYNC_GET_HALT, &eCurrentHalt);
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| +**   assert( eNewHalt==eCurrentHalt );
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| +**
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| +** See below for more detail on each configuration parameter.
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| +**
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| +** SQLITEASYNC_HALT:
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| +**
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| +**   This is used to set the value of the "halt" parameter. The second
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| +**   argument must be one of the SQLITEASYNC_HALT_XXX symbols defined
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| +**   below (either NEVER, IDLE and NOW).
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| +**
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| +**   If the parameter is set to NEVER, then calls to sqlite3async_run()
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| +**   never return. This is the default setting. If the parameter is set
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| +**   to IDLE, then calls to sqlite3async_run() return as soon as the
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| +**   queue of pending write operations is empty. If the parameter is set
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| +**   to NOW, then calls to sqlite3async_run() return as quickly as 
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| +**   possible, without processing any pending write requests.
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| +**
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| +**   If an attempt is made to set this parameter to an integer value other
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| +**   than SQLITEASYNC_HALT_NEVER, IDLE or NOW, then sqlite3async_control() 
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| +**   returns SQLITE_MISUSE and the current value of the parameter is not 
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| +**   modified.
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| +**
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| +**   Modifying the "halt" parameter affects calls to sqlite3async_run() 
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| +**   made by other threads that are currently in progress.
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| +**
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| +** SQLITEASYNC_DELAY:
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| +**
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| +**   This is used to set the value of the "delay" parameter. If set to
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| +**   a non-zero value, then after completing a pending write request, the
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| +**   sqlite3async_run() function sleeps for the configured number of 
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| +**   milliseconds.
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| +**
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| +**   If an attempt is made to set this parameter to a negative value,
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| +**   sqlite3async_control() returns SQLITE_MISUSE and the current value
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| +**   of the parameter is not modified.
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| +**
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| +**   Modifying the "delay" parameter affects calls to sqlite3async_run() 
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| +**   made by other threads that are currently in progress.
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| +**
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| +** SQLITEASYNC_LOCKFILES:
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| +**
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| +**   This is used to set the value of the "lockfiles" parameter. This
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| +**   parameter must be set to either 0 or 1. If set to 1, then the
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| +**   asynchronous IO VFS uses the xLock() and xUnlock() methods of the
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| +**   parent VFS to lock database files being read and/or written. If
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| +**   the parameter is set to 0, then these locks are omitted.
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| +**
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| +**   This parameter may only be set when there are no open database
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| +**   connections using the VFS and the queue of pending write requests
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| +**   is empty. Attempting to set it when this is not true, or to set it 
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| +**   to a value other than 0 or 1 causes sqlite3async_control() to return
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| +**   SQLITE_MISUSE and the value of the parameter to remain unchanged.
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| +**
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| +**   If this parameter is set to zero, then it is only safe to access the
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| +**   database via the asynchronous IO VFS from within a single process. If
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| +**   while writing to the database via the asynchronous IO VFS the database
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| +**   is also read or written from within another process, or via another
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| +**   connection that does not use the asynchronous IO VFS within the same
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| +**   process, the results are undefined (and may include crashes or database
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| +**   corruption).
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| +**
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| +**   Alternatively, if this parameter is set to 1, then it is safe to access
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| +**   the database from multiple connections within multiple processes using
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| +**   either the asynchronous IO VFS or the parent VFS directly.
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| +*/
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| +int sqlite3async_control(int op, ...);
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| +
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| +/*
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| +** Values that can be used as the first argument to sqlite3async_control().
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| +*/
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| +#define SQLITEASYNC_HALT          1
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| +#define SQLITEASYNC_GET_HALT      2
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| +#define SQLITEASYNC_DELAY         3
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| +#define SQLITEASYNC_GET_DELAY     4
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| +#define SQLITEASYNC_LOCKFILES     5
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| +#define SQLITEASYNC_GET_LOCKFILES 6
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| +
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| +/*
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| +** If the first argument to sqlite3async_control() is SQLITEASYNC_HALT,
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| +** the second argument should be one of the following.
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| +*/
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| +#define SQLITEASYNC_HALT_NEVER 0       /* Never halt (default value) */
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| +#define SQLITEASYNC_HALT_NOW   1       /* Halt as soon as possible */
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| +#define SQLITEASYNC_HALT_IDLE  2       /* Halt when write-queue is empty */
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| +
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| +#ifdef __cplusplus
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| +}  /* End of the 'extern "C"' block */
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| +#endif
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| +#endif        /* ifndef __SQLITEASYNC_H_ */
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| +
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| 
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