Berkeley DB: db_env_set_func_seek
Description: Berkeley DB: An embedded database programmatic toolkit.
Keywords: embedded,database,programmatic,toolkit,b+tree,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,Java,C,C++

### db_env_set_func_seek |

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    #include <db.h>

    int
    db_env_set_func_seek(int (*func_seek)(int fd, size_t pgsize,
        db_pgno_t pageno, u_int32_t relative, int rewind, int whence));

### Description: db_env_set_func_seek

The Berkeley DB library requires the ability to specify that a subsequent read from or write to a file will occur at a specific location in that file.

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

### Parameters

func_seek
  The func_seek parameter is the function which seeks to a specific location in a file.

  The fd parameter is an open file descriptor on the file.

  The seek function must cause a subsequent read from or write to the file to occur at a byte offset specified by the calculation:

  >     (pgsize * pageno) + relative

  If rewind is non-zero, the byte offset is treated as a backward seek, not a forward one.

  The whence parameter specifies where in the file the byte offset is relative to, as described by the IEEE/ANSI Std 1003.1 (POSIX) lseek system call.

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

### See Also

Run-time configuration`

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