Berkeley DB: db_env_set_tas_spins
Description: Berkeley DB: An embedded database programmatic toolkit.
Keywords: embedded,database,programmatic,toolkit,b+tree,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,java,C,C++

# db_env_set_tas_spins |

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    #include <db.h>

    int
    db_env_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 db_env_set_tas_spins interface affects the entire application, not a single database or database environment.

While the db_env_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 functions.

The db_env_set_tas_spins function returns a non-zero error value on failure and 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.

# See Also

DBENV->close, db_env_create, DBENV->open, DBENV->remove, DBENV->err, db_strerror, db_version, DBENV->set_cachesize, DBENV->set_errcall, DBENV->set_errfile, DBENV->set_errpfx, DBENV->set_flags, DBENV->set_mutexlocks, DBENV->set_paniccall, and DBENV->set_verbose.`

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