#include <db_cxx.h>

static int
DbEnv::set_tas_spins(u_int32_t tas_spins);

Description

Specify that test-and-set mutexes should spin tas_spins times without blocking. The value defaults to 1 on uniprocessor systems and to 50 times the number of processors on multiprocessor systems.

The DbEnv::set_tas_spins interface affects the entire application, not a single database or database environment.

While the DbEnv::set_tas_spins interface may be used to configure Berkeley DB at any time during the life of the application, it should normally be called before making any calls to the db_env_create or db_create methods.

The DbEnv::set_tas_spins 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 database environment's test-and-set spin count may also be set using the environment's DB_CONFIG file. The syntax of the entry in that file is a single line with the string "set_tas_spins", one or more whitespace characters, and the number of spins. Because the DB_CONFIG file is read when the database environment is opened, it will silently overrule configuration done before that time.

Errors

EINVAL

An invalid flag value or parameter was specified.

Class

See Also