### db_env_set_func_unmap

`

###

    #include <db.h>

    int
    db_env_set_func_unmap(int (*func_unmap)(void *addr, size_t len));

### Description: db_env_set_func_unmap

The Berkeley DB library requires the ability to unmap a file or shared memory region from memory.

The db_env_set_func_unmap method configures all operations performed by a process and all of its threads of control, not operations confined to a single database environment.

Although the db_env_set_func_unmap method may be called at any time during the life of the application, it should normally be called before making calls to the db_env_create or db_create methods.

The db_env_set_func_unmap method returns a non-zero error value on failure and 0 on success.

### Parameters

func_unmap
  The func_unmap parameter is the function which unmaps a file or shared memory region.

  The addr parameter is the value returned by the db_env_set_func_map function when the file or region was mapped into memory, and the len parameter is the same as the len parameter specified to the db_env_set_func_map function when the file or region was mapped into memory.

  The func_unmap function must return the value of errno on failure and 0 on success.

### See Also

Run-time configuration`

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