joey shelton / LED_Demo

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Dependencies:   MAX44000 PWM_Tone_Library nexpaq_mdk

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FileHandle Class Reference
Public Member Functions | Protected Member Functions

FileHandle Class Reference

An OO equivalent of the internal FILEHANDLE variable and associated _sys_* functions. More...

#include <FileHandle.h>

Inherited by FATFileHandle, FileLike, and LocalFileHandle.

Public Member Functions

virtual ssize_t write (const void *buffer, size_t length)=0
 Write the contents of a buffer to the file.
virtual int close ()=0
 Close the file.
virtual ssize_t read (void *buffer, size_t length)=0
 Function read Reads the contents of the file into a buffer.
virtual int isatty ()=0
 Check if the handle is for a interactive terminal device.
virtual off_t lseek (off_t offset, int whence)=0
 Move the file position to a given offset from a given location.
virtual int fsync ()=0
 Flush any buffers associated with the FileHandle, ensuring it is up to date on disk.

Protected Member Functions

virtual void lock ()
 Acquire exclusive access to this object.
virtual void unlock ()
 Release exclusive access to this object.

Detailed Description

An OO equivalent of the internal FILEHANDLE variable and associated _sys_* functions.

FileHandle is an abstract class, needing at least sys_write and sys_read to be implmented for a simple interactive device.

No one ever directly tals to/instanciates a FileHandle - it gets created by FileSystem, and wrapped up by stdio.

Synchronization level: Set by subclass

Definition at line 44 of file FileHandle.h.

Member Function Documentation

virtual int close (  ) [pure virtual]

Close the file.

Returns:
Zero on success, -1 on error.

Implemented in Stream.

virtual int fsync (  ) [pure virtual]

Flush any buffers associated with the FileHandle, ensuring it is up to date on disk.

Returns:
0 on success or un-needed, -1 on error

Implemented in Stream.

virtual int isatty (  ) [pure virtual]

Check if the handle is for a interactive terminal device.

If so, line buffered behaviour is used by default

Returns:
1 if it is a terminal, 0 otherwise

Implemented in Stream.

virtual void lock ( void   ) [protected, virtual]

Acquire exclusive access to this object.

Reimplemented in Serial.

Definition at line 127 of file FileHandle.h.

virtual off_t lseek ( off_t  offset,
int  whence 
) [pure virtual]

Move the file position to a given offset from a given location.

Parameters:
offsetThe offset from whence to move to
whenceSEEK_SET for the start of the file, SEEK_CUR for the current file position, or SEEK_END for the end of the file.
Returns:
new file position on success, -1 on failure or unsupported

Implemented in Stream.

virtual ssize_t read ( void *  buffer,
size_t  length 
) [pure virtual]

Function read Reads the contents of the file into a buffer.

Parameters:
bufferthe buffer to read in to
lengththe number of characters to read
Returns:
The number of characters read (zero at end of file) on success, -1 on error.

Implemented in Stream.

virtual void unlock ( void   ) [protected, virtual]

Release exclusive access to this object.

Reimplemented in Serial.

Definition at line 133 of file FileHandle.h.

virtual ssize_t write ( const void *  buffer,
size_t  length 
) [pure virtual]

Write the contents of a buffer to the file.

Parameters:
bufferthe buffer to write from
lengththe number of characters to write
Returns:
The number of characters written (possibly 0) on success, -1 on error.

Implemented in Stream.

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