---
name: "ost_RandomFile"
section: "3"
platform: "linux"
package: "libcommoncpp2-doc"
version: "1.8.1-10"
release: "Debian 11 (Bullseye)"
platforms: ["linux"]
url: "https://new.carta.tech/ost_RandomFile"
---

# ost\_RandomFile(3)

The purpose of this class is to define a base class for low level random file access that is portable between Win32 and Posix systems.

## NAME

ost::RandomFile - The purpose of this class is to define a base class for low level random file access that is portable between Win32 and Posix systems.

## SYNOPSIS

`#include <file.h>`

Inherits **ost::Mutex**, and **ost::File**.

Inherited by **ost::MappedFile**, **ost::SharedFile**, and **ost::ThreadFile**.

### Public Member Functions

virtual **~RandomFile** ()\
 Destroy a random access file or it's derived class.  bool **initial** (void)\
 This method should be called right after a **RandomFile** derived object has been created.  off\_t **getCapacity** (void)\
 Get current file capacity.  virtual **Error** **restart** (void)\
 This method is commonly used to close and re-open an existing database.  **Error** **getErrorNumber** (void)\
 Return current error id.  char \* **getErrorString** (void)\
 Return current error string.  bool **operator!** (void)\

### Protected Member Functions

**RandomFile** (const char \*name=NULL)\
 Create an unopened random access file.  **RandomFile** (const **RandomFile** &rf)\
 Default copy constructor.  **Error** **error** (**Error** errid, char \*errstr=NULL)\
 Post an error event.  **Error** **error** (char \*err)\
 Post an extended string error message.  void **setError** (bool enable)\
 Used to enable or disable throwing of exceptions on errors.  **Error** **setCompletion** (**Complete** mode)\
 Used to set file completion modes.  void **setTemporary** (bool enable)\
 Used to set the temporary attribute for the file.  virtual **Attr** **initialize** (void)\
 This method is used to initialize a newly created file as indicated by the 'initial' flag.  void **final** (void)\
 Close the file.

### Protected Attributes

int **fd**\
 **Access** **access**\
 char \* **pathname**\
 struct {\
    unsigned **count**: 16\
    bool **thrown**: 1\
    bool **initial**: 1\
    bool **immediate**: 1\
    bool **temp**: 1\
 } **flags**\

### Related Functions

(Note that these are not member functions.)  bool **\_\_EXPORT** **isDir** (const char \*path)\
 bool **\_\_EXPORT** **isFile** (const char \*path)\
 bool **\_\_EXPORT** **isDevice** (const char \*path)\
 bool **\_\_EXPORT** **canAccess** (const char \*path)\
 bool **\_\_EXPORT** **canModify** (const char \*path)\
 time\_t **\_\_EXPORT** **lastModified** (const char \*path)\
 time\_t **\_\_EXPORT** **lastAccessed** (const char \*path)\

### Additional Inherited Members

## Detailed Description

The purpose of this class is to define a base class for low level random file access that is portable between Win32 and Posix systems.

This class is a foundation both for optimized thread shared and traditional locked file access that is commonly used to build database services, rather than the standard C++ streaming file classes.

**Author**

David Sugar dyfet@ostel.com

Portable random disk file access.

## Constructor & Destructor Documentation

### ost::RandomFile::RandomFile (const char \* name = `NULL`)` [protected]`

Create an unopened random access file.

### ost::RandomFile::RandomFile (const RandomFile & rf)` [protected]`

Default copy constructor.

### virtual ost::RandomFile::~RandomFile ()` [virtual]`

Destroy a random access file or it's derived class.

## Member Function Documentation

### Error ost::RandomFile::error (char \* err)` [inline]`, ` [protected]`

Post an extended string error message.

**Returns**

errExtended.

**Parameters**

*err* error string.

References ost::error().

### Error ost::RandomFile::error (Error errid, char \* errstr = `NULL`)` [protected]`

Post an error event.

**Returns**

error code.

**Parameters**

*errid* error code. \
 *errstr* error message string.

### void ost::RandomFile::final (void)` [protected]`

Close the file.

### off\_t ost::RandomFile::getCapacity (void)

Get current file capacity.

**Returns**

total file size.

### Error ost::RandomFile::getErrorNumber (void)` [inline]`

Return current error id.

**Returns**

last error identifier set.

### char\* ost::RandomFile::getErrorString (void)` [inline]`

Return current error string.

**Returns**

last error string set.

### bool ost::RandomFile::initial (void)

This method should be called right after a **RandomFile** derived object has been created. This method will invoke initialize if the object is newly created, and set file access permissions appropriately.

**Returns**

true if file had to be initialized.

### virtual Attr ost::RandomFile::initialize (void)` [protected]`, ` [virtual]`

This method is used to initialize a newly created file as indicated by the 'initial' flag. This method also returns the file access permissions that should be associated with the file. This method should never be called directly, but is instead used to impliment the 'Initial' method. Typically one would use this to build an empty database shell when a previously empty database file is created.

**Returns**

access, or attrInvalid if should be removed.

### bool ost::RandomFile::operator! (void)

### virtual Error ost::RandomFile::restart (void)` [virtual]`

This method is commonly used to close and re-open an existing database. This may be used when the database has been unlinked and an external process provides a new one to use.

Reimplemented in **ost::SharedFile**, and **ost::ThreadFile**.

### Error ost::RandomFile::setCompletion (Complete mode)` [protected]`

Used to set file completion modes.

**Returns**

errSuccess if okay.

**Parameters**

*mode* completion mode.

### void ost::RandomFile::setError (bool enable)` [inline]`, ` [protected]`

Used to enable or disable throwing of exceptions on errors.

**Parameters**

*enable* true if errors will be thrown.

### void ost::RandomFile::setTemporary (bool enable)` [inline]`, ` [protected]`

Used to set the temporary attribute for the file. Temporary files are automatically deleted when closed.

**Parameters**

*enable* true for marking as temporary.

## Friends And Related Function Documentation

### bool \_\_EXPORT canAccess (const char \* path)` [related]`

### bool \_\_EXPORT canModify (const char \* path)` [related]`

### bool \_\_EXPORT isDevice (const char \* path)` [related]`

### bool \_\_EXPORT isDir (const char \* path)` [related]`

### bool \_\_EXPORT isFile (const char \* path)` [related]`

### time\_t \_\_EXPORT lastAccessed (const char \* path)` [related]`

### time\_t \_\_EXPORT lastModified (const char \* path)` [related]`

## Member Data Documentation

### Access ost::RandomFile::access` [protected]`

### unsigned ost::RandomFile::count

### int ost::RandomFile::fd` [protected]`

### struct { ... } ost::RandomFile::flags` [protected]`

### bool ost::RandomFile::immediate

### bool ost::RandomFile::initial

### char\* ost::RandomFile::pathname` [protected]`

### bool ost::RandomFile::temp

### bool ost::RandomFile::thrown

## Author

Generated automatically by Doxygen for GNU CommonC++ from the source code.