#include <db.h>

int
DB_ENV->mutex_set_increment(DB_ENV *dbenv, u_int32_t increment);  

Configure the number of additional mutexes to allocate.

If an application will allocate mutexes for its own use, the DB_ENV->mutex_set_increment() method is used to add a number of mutexes to the default allocation.

Calling the DB_ENV->mutex_set_increment() method discards any value previously set using the DB_ENV->mutex_set_max() method.

The database environment's number of additional mutexes 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 "mutex_set_increment", one or more whitespace characters, and the number of additional mutexes. Because the DB_CONFIG file is read when the database environment is opened, it will silently overrule configuration done before that time.

The DB_ENV->mutex_set_increment() method configures a database environment, not only operations performed using the specified DB_ENV handle.

The DB_ENV->mutex_set_increment() method may not be called after the DB_ENV->open() method is called. If the database environment already exists when DB_ENV->open() is called, the information specified to DB_ENV->mutex_set_increment() will be ignored.

The DB_ENV->mutex_set_increment() method returns a non-zero error value on failure and 0 on success.