task_share.Share Class Reference

This class implements a shared data item which can be protected against data corruption by pre-emptive multithreading. More...

Public Member Functions
def	__init__ (self, type_code, thread_protect=True, name=None)
	Allocate memory in which the shared data will be buffered. More...
def	put (self, data, in_ISR=False)
	Write an item of data into the share. More...
def	get (self, in_ISR=False)
	Read an item of data from the share. More...
def	__repr__ (self)
	This method puts diagnostic information about the share into a string.

Static Public Attributes
int	ser_num = 0
	A counter used to give serial numbers to shares for diagnostic use.

Detailed Description

This class implements a shared data item which can be protected against data corruption by pre-emptive multithreading.

Multithreading which can corrupt shared data includes the use of ordinary interrupts as well as the use of a Real-Time Operating System (RTOS).

Constructor & Destructor Documentation

__init__()

def task_share.Share.__init__	(		self,
			type_code,
			thread_protect = True,
			name = None
	)

Allocate memory in which the shared data will be buffered.

The data type code is given as for the Python 'array' type, which can be any of

• b (signed char), B (unsigned char)
• h (signed short), H (unsigned short)
• i (signed int), I (unsigned int)
• l (signed long), L (unsigned long)
• q (signed long long), Q (unsigned long long)
• f (float), or d (double-precision float)

  Parameters

  type_code	The type of data items which the share can hold
  thread_protect	True if mutual exclusion protection is used
  name	A short name for the share, default ShareN where N is a serial number for the share

Member Function Documentation

get()

def task_share.Share.get	(		self,
			in_ISR = False
	)

Read an item of data from the share.

Interrupts are disabled as the data is read so as to prevent data corruption by changes in the data as it is being read.

Parameters

in_ISR

Set this to True if calling from within an ISR

put()

def task_share.Share.put	(		self,
			data,
			in_ISR = False
	)

Write an item of data into the share.

Any old data is overwritten. This code disables interrupts during the writing so as to prevent data corrupting by an interrupt service routine which might access the same data.

Parameters

data	The data to be put into this share
in_ISR	Set this to True if calling from within an ISR

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The documentation for this class was generated from the following file:

• task_share.py