IoTivity-Lite
Protothreads

Modules

 Local continuations
 Local continuations form the basis for implementing protothreads.
 
 Protothread semaphores
 This module implements counting semaphores on top of protothreads.
 

Files

file  pt.h
 Protothreads implementation.
 

Macros

#define PT_ENDED   3
 
#define PT_EXITED   2
 
#define PT_WAITING   0
 
#define PT_YIELDED   1
 

Initialization

#define PT_INIT(pt)
 Initialize a protothread. More...
 

Declaration and definition

#define PT_THREAD(name_args)
 Declaration of a protothread. More...
 
#define PT_BEGIN(pt)
 Declare the start of a protothread inside the C function implementing the protothread. More...
 
#define PT_END(pt)
 Declare the end of a protothread. More...
 

Blocked wait

#define PT_WAIT_UNTIL(pt, condition)
 Block and wait until condition is true. More...
 
#define PT_WAIT_WHILE(pt, cond)
 Block and wait while condition is true. More...
 

Hierarchical protothreads

#define PT_WAIT_THREAD(pt, thread)
 Block and wait until a child protothread completes. More...
 
#define PT_SPAWN(pt, child, thread)
 Spawn a child protothread and wait until it exits. More...
 

Exiting and restarting

#define PT_RESTART(pt)
 Restart the protothread. More...
 
#define PT_EXIT(pt)
 Exit the protothread. More...
 

Calling a protothread

#define PT_SCHEDULE(f)
 Schedule a protothread. More...
 

Yielding from a protothread

#define PT_YIELD(pt)
 Yield from the current protothread. More...
 
#define PT_YIELD_UNTIL(pt, cond)
 Yield from the protothread until a condition occurs. More...
 

Detailed Description

Macro Definition Documentation

◆ PT_BEGIN

#define PT_BEGIN (   pt)

Declare the start of a protothread inside the C function implementing the protothread.

This macro is used to declare the starting point of a protothread. It should be placed at the start of the function in which the protothread runs. All C statements above the PT_BEGIN() invokation will be executed each time the protothread is scheduled.

Parameters
ptA pointer to the protothread control structure.

◆ PT_END

#define PT_END (   pt)

Declare the end of a protothread.

This macro is used for declaring that a protothread ends. It must always be used together with a matching PT_BEGIN() macro.

Parameters
ptA pointer to the protothread control structure.

◆ PT_EXIT

#define PT_EXIT (   pt)

Exit the protothread.

This macro causes the protothread to exit. If the protothread was spawned by another protothread, the parent protothread will become unblocked and can continue to run.

Parameters
ptA pointer to the protothread control structure.

◆ PT_INIT

#define PT_INIT (   pt)

Initialize a protothread.

Initializes a protothread. Initialization must be done prior to starting to execute the protothread.

Parameters
ptA pointer to the protothread control structure.
See also
PT_SPAWN()

◆ PT_RESTART

#define PT_RESTART (   pt)

Restart the protothread.

This macro will block and cause the running protothread to restart its execution at the place of the PT_BEGIN() call.

Parameters
ptA pointer to the protothread control structure.

◆ PT_SCHEDULE

#define PT_SCHEDULE (   f)

Schedule a protothread.

This function schedules a protothread. The return value of the function is non-zero if the protothread is running or zero if the protothread has exited.

Parameters
fThe call to the C function implementing the protothread to be scheduled

◆ PT_SPAWN

#define PT_SPAWN (   pt,
  child,
  thread 
)

Spawn a child protothread and wait until it exits.

This macro spawns a child protothread and waits until it exits. The macro can only be used within a protothread.

Parameters
ptA pointer to the protothread control structure.
childA pointer to the child protothread's control structure.
threadThe child protothread with arguments

◆ PT_THREAD

#define PT_THREAD (   name_args)

Declaration of a protothread.

This macro is used to declare a protothread. All protothreads must be declared with this macro.

Parameters
name_argsThe name and arguments of the C function implementing the protothread.

◆ PT_WAIT_THREAD

#define PT_WAIT_THREAD (   pt,
  thread 
)

Block and wait until a child protothread completes.

This macro schedules a child protothread. The current protothread will block until the child protothread completes.

Note
The child protothread must be manually initialized with the PT_INIT() function before this function is used.
Parameters
ptA pointer to the protothread control structure.
threadThe child protothread with arguments
See also
PT_SPAWN()

◆ PT_WAIT_UNTIL

#define PT_WAIT_UNTIL (   pt,
  condition 
)

Block and wait until condition is true.

This macro blocks the protothread until the specified condition is true.

Parameters
ptA pointer to the protothread control structure.
conditionThe condition.

◆ PT_WAIT_WHILE

#define PT_WAIT_WHILE (   pt,
  cond 
)

Block and wait while condition is true.

This function blocks and waits while condition is true. See PT_WAIT_UNTIL().

Parameters
ptA pointer to the protothread control structure.
condThe condition.

◆ PT_YIELD

#define PT_YIELD (   pt)

Yield from the current protothread.

This function will yield the protothread, thereby allowing other processing to take place in the system.

Parameters
ptA pointer to the protothread control structure.

◆ PT_YIELD_UNTIL

#define PT_YIELD_UNTIL (   pt,
  cond 
)

Yield from the protothread until a condition occurs.

Parameters
ptA pointer to the protothread control structure.
condThe condition.
        This function will yield the protothread, until the
        specified condition evaluates to true.