# DbEnv::set_tas_spins

`

###

    #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 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. Configuration in the DB_CONFIG file silently overrules configuration done using the DbEnv::set_tas_spins method.

# Errors

EINVAL
  An invalid flag value or parameter was specified.

### Class

DbEnv

# See Also

DbEnv::close, DbEnv::open, DbEnv::remove, DbEnv::err, DbEnv::strerror, DbEnv::version, DbEnv::set_cachesize, DbEnv::set_errcall, DbEnv::set_errfile, DbEnv::set_error_stream, DbEnv::set_errpfx, DbEnv::set_paniccall, and DbEnv::set_verbose.`

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