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Semaphores

Semaphores are mainly used for inter-process communication or communication with external systems.

The system has 256 built-in semaphores, indexed from 0 to 255. Each semaphore can store a 32-bit integer value, ranging from -2147483648 to 2147483647.

After the system restarts, all semaphores will be reset to 0.

Set Semaphore auto_sync

set_signal(index, value)
  • Parameters
    • index: Semaphore index.
    • value: Value to be set for the semaphore.

Increase Semaphore Value auto_sync

add_signal(index, value)
  • Parameters
    • index: Semaphore index.
    • value: Value to be added to the semaphore.
  • Returns
    • The value of the semaphore after the increase. Overflow may occur.

Set Multiple Semaphores auto_sync

set_signals(index, values)
  • Parameters
    • index: Starting index of semaphores.
    • values: Values to be set for the semaphores.
Example Program
set_signals(1, {1,2,3})

Get Semaphore

get_signal(index)

  • Parameters

    • index: Semaphore index.

  • Returns

    • The value of the corresponding semaphore.

Get Multiple Semaphores

values = get_signals(index, len)
  • Parameters
    • index: Starting index of semaphores.
    • len: Number of semaphores to get.
Example Program
values = set_signals(1, 3)
print(values)

Wait for Semaphore auto_sync

wait_signal(index, value, relation)

Example

set_signal(1, 2147483647)
print(get_signal(1))
add_signal(1, 2)
print(get_signal(1))