Library Version 18.1.40

DbEnv::mutex_set_tas_spins()
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## DbEnv::mutex_set_tas_spins()

    #include <db_cxx.h>

    int
    DbEnv::mutex_set_tas_spins(u_int32_t tas_spins);

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, up to a maximum of 200.

The database environment's test-and-set spin count may also be configured 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.

The `DbEnv::mutex_set_tas_spins()` method configures operations performed using the specified DbEnv handle, not all operations performed on the underlying database environment.

The `DbEnv::mutex_set_tas_spins()` method may be called at any time during the life of the application.

The `DbEnv::mutex_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.

### Parameters

#### tas_spins

The tas_spins parameter is the number of spins test-and-set mutexes should execute before blocking.

### Errors

The `DbEnv::mutex_set_tas_spins()` 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:

#### EINVAL

An invalid flag value or parameter was specified.

### Class

DbEnv

### See Also

Mutex Methods

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