# Berkeley DB: DbEnv::set_isalive
Berkeley DB: An embedded database programmatic toolkit.
Keywords: embedded,database,programmatic,toolkit,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,Java,C,C++

DbEnv::set_isalive |

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    #include <db_cxx.h>

    int
    DbEnv::set_isalive(int (*is_alive)(DbEnv *dbenv, pid_t pid, db_threadid_t tid, u_int32_t flags));

Description: DbEnv::set_isalive

Declare a function that returns if a thread of control (either a true thread or a process) is still running. The DbEnv::set_isalive method supports the DbEnv::failchk method. For more information, see Architecting Data Store and Concurrent Data Store applications, and Architecting Transactional Data Store applications.

The DbEnv::set_isalive method configures operations performed using the specified DbEnv handle, not all operations performed on the underlying database environment.

The DbEnv::set_isalive method may be called at any time during the life of the application.

The DbEnv::set_isalive 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
is_alive

- The is_alive parameter is a function which returns non-zero if the thread of control, identified by the pid and tid arguments, is still running. The function takes four arguments:

dbenv

- The dbenv parameter is the enclosing database environment handle, allowing application access to the application-private fields of that object.

pid

- The pid parameter is a process ID returned by the function specified to the DbEnv::set_thread_id method.

tid

- The tid parameter is a thread ID returned by the function specified to the DbEnv::set_thread_id method.

flags

- The flags parameter must be set to 0 or the following value:
  DB_MUTEX_PROCESS_ONLY
  - Return only if the process is alive, the thread ID should be ignored.

Errors

The DbEnv::set_isalive method may fail and throw DbException, 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 Database Environments and Related Methods`

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