#include <file.h>
Inheritance diagram for SharedFile:

Public Methods | |
| SharedFile (const char *path) | |
| Open or create a new database file. More... | |
| SharedFile (const SharedFile &file) | |
| Create a shared file as a duplicate of an existing shared file. More... | |
| ~SharedFile () | |
| Close and finish a database file. | |
| fileerror_t | Restart (void) |
| Restart an existing database; close and re-open. More... | |
| fileerror_t | Fetch (caddr_t address = NULL, size_t length = 0, off_t position = - 1) |
| Lock and Fetch a portion of the file into physical memory. More... | |
| fileerror_t | Update (caddr_t address = NULL, size_t length = 0, off_t position = -1) |
| Update a portion of a file from physical memory. More... | |
| fileerror_t | Clear (size_t length = 0, off_t pos = -1) |
| Clear a lock held from a previous fetch operation without updating. More... | |
| fileerror_t | Append (caddr_t address = NULL, size_t length = 0) |
| Add new data to the end of the file. More... | |
| off_t | getPosition (void) |
| Fetch the current file position marker for this thread. More... | |
| bool | operator++ (void) |
| bool | operator-- (void) |
Each thread should access a dup of the database object, and mutex locks can be used to preserve transaction integrety if multiple threads are used.
SharedFile is used when a database may be shared between multiple processes. SharedFile automatically applies low level byte-range "file locks", and provides an interface to fetch and release byte-range locked portions of a file.
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Open or create a new database file. You should also use Initial.
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Create a shared file as a duplicate of an existing shared file.
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Close and finish a database file.
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Add new data to the end of the file. Locks file during append.
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Clear a lock held from a previous fetch operation without updating.
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Lock and Fetch a portion of the file into physical memory. This can use state information to fetch the current record multiple times.
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Restart an existing database; close and re-open.
Reimplemented from RandomFile. |
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Update a portion of a file from physical memory. This can use state information to commit the last read record. The current lock is also cleared.
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Fetch the current file position marker for this thread.
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1.2.1 written by Dimitri van Heesch,
© 1997-2000