#include <db_cxx.h> int DbEnv::mutex_alloc(u_int32_t flags, db_mutex_t *mutexp);
The DbEnv::mutex_alloc() method allocates a mutex and returns a
reference to it into the memory specified by mutexp.
The DbEnv::mutex_alloc() method may not be called before the
DbEnv::open() method is called.
The DbEnv::mutex_alloc()
method either returns a non-zero error value or throws an
exception that encapsulates a non-zero error value on
failure, and returns 0 on success.
The flags parameter must be set to 0 or by bitwise inclusively OR'ing together one or more of the following values:
The mutex is associated with a single process. The DbEnv::failchk() method will release mutexes held by any process which has exited.
The mutex must be self-blocking. That is, if a thread of control
locks the mutex and then attempts to lock the mutex again, the thread
of control will block until another thread of control releases the
original lock on the mutex, allowing the original thread of control to
lock the mutex the second time. Attempting to re-acquire a mutex for
which the DB_MUTEX_SELF_BLOCK flag was not specified will result in
undefined behavior.
The DbEnv::mutex_alloc()
method may fail and throw a DbException
exception, encapsulating one of the following non-zero errors, or return one
of the following non-zero errors: