ost::SharedFile(3)

💖 ost::SharedFile — from the Library Functions Manual (that's ost::SharedFile(3), bestie, section 3, C++ library calls, iykyk) ✨

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🌸 NAME 🌸

ost::SharedFile — this class defines a database I/O file service that can be shared by multiple processes. 💅

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🎀 SYNOPSIS 🎀

#include <file.h>

Inherits ost::RandomFile. Yes queen, it's giving inheritance. 👑

✨ Public Member Functions ✨

• SharedFile (const char *path) — open or create a new database file.
• SharedFile (const SharedFile &file) — create a shared file as a duplicate of an existing shared file.
• virtual ~SharedFile () — close and finish a database file.
• Error restart (void) — restart an existing database; close and re-open.
• Error fetch (caddr_t address=NULL, ccxx_size_t length=0, off_t position=-1) — lock and fetch a portion of the file into physical memory.
• Error update (caddr_t address=NULL, ccxx_size_t length=0, off_t position=-1) — update a portion of a file from physical memory.
• Error clear (ccxx_size_t length=0, off_t pos=-1) — clear a lock held from a previous fetch operation without updating.
• Error append (caddr_t address=NULL, ccxx_size_t length=0) — add new data to the end of the file.
• off_t getPosition (void) — fetch the current file position marker for this thread.
• bool operator++ (void)
• bool operator-- (void)

🌈 Additional Inherited Members 🌈

(they're in the family tree, she's just not listing them all here 🫶)

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💜 Detailed Description 💜

This class defines a database I/O file service that can be shared by multiple processes. no cap

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. The way it just... handles the locking for you?? main character energy fr fr. 💅

Author

• David Sugar dyfet@ostel.com

This class defines a database I/O file service that can be shared by multiple processes. (saying it twice because she's iconic like that ✨)

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🦋 Constructor & Destructor Documentation 🦋

ost::SharedFile::SharedFile (const char * path)

Open or create a new database file. You should also use Initial. 🍼

Parameters

• path — pathname of database to open.

ost::SharedFile::SharedFile (const SharedFile & file)

Create a shared file as a duplicate of an existing shared file. copy-paste but make it ✨intentional✨

Parameters

• file — original file.

virtual ost::SharedFile::~SharedFile () [virtual]

Close and finish a database file. she's done, she's logging off, closing the door gently 🚪💖

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🌟 Member Function Documentation 🌟

Error ost::SharedFile::append (caddr_t address = NULL, ccxx_size_t length = 0)

Add new data to the end of the file. Locks file during append. 🔐

Parameters

• address — address to use, or NULL if same as last I/O.
• length — length to use, or 0 if same as last I/O.

Error ost::SharedFile::clear (ccxx_size_t length = 0, off_t pos = -1)

Clear a lock held from a previous fetch operation without updating. releasing the grip, respectfully 🙈

Returns

• errSuccess on success.

Parameters

• length — length to use, or 0 if same as last I/O.
• pos — file position to use or -1 if same as last I/O.

Error ost::SharedFile::fetch (caddr_t address = NULL, ccxx_size_t length = 0, off_t position = -1)

Lock and Fetch a portion of the file into physical memory. This can use state information to fetch the current record multiple times. 🧠✨

Returns

• errSuccess on success.

Parameters

• address — address to use, or NULL if same as last I/O.
• length — length to use, or 0 if same as last I/O.
• position — file position to use -1 if same as last I/O.

off_t ost::SharedFile::getPosition (void)

Fetch the current file position marker for this thread. where are we? spiritually? also byte-wise. 📍

Returns

• file position offset.

bool ost::SharedFile::operator++ (void)

bool ost::SharedFile::operator-- (void)

(yes bestie, they're just listed. no description. not everything needs a paragraph 💀)

Error ost::SharedFile::restart (void) [inline], [virtual]

Restart an existing database; close and re-open. it's giving rebirth arc 🦋

Returns

• errSuccess if successful.

Reimplemented from ost::RandomFile.

Error ost::SharedFile::update (caddr_t address = NULL, ccxx_size_t length = 0, off_t position = -1)

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. committing AND letting go?? growth. 🌱

Returns

• errSuccess on success.

Parameters

• address — address to use, or NULL if same as last I/O.
• length — length to use, or 0 if same as last I/O.
• position — file position to use or -1 if same as last I/O.

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👑 Author 👑

Generated automatically by Doxygen for GNU CommonC++ from the source code. the robots wrote the docs, we just made them cute 💅

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okay that's the whole page bestie, every flag, every default, every errSuccess, all of it — nothing skipped, nothing invented. go forth and lock some byte ranges. 🫶✨

GNU CommonC++ · Sun Dec 27 2020 · mwah, that's the version and date, love u, bye 💖🎀🦋🌸