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osMessageCreate() Question

Keaven Pineau

Hello everyone,

I tried to find the use for the ThreadId parameter and I dont find it anywhere. Why we would need to pass a ThreadId to the message queue?

Let's say I am using osWaitForever in my thread calling osMessageGet() and I want the kill the thread how to I unblock osMessageGet()? Is it where the parameter mentionned above come into play?

Regards,

Parents
  • 0

    Yes there is a timeout value in the command according to the webpage

    osEvent osMessageGet ( osMessageQId queue_id, uint32_t millisec )

    Parameters
    [in] queue_id message queue ID obtained with osMessageCreate.
    [in] millisec timeout value or 0 in case of no time-out.
    Returnsevent information that includes status code. NoteMUST REMAIN UNCHANGED: osMessageGet shall be consistent in every CMSIS-RTOS.
    Suspend the execution of the current RUNNING thread until a message arrives. When a message is already in the queue, the function returns instantly with the message information.

    The argument millisec specifies how long the system waits for a message to become available. While the system waits the thread that is calling this function is put into the state WAITING. The millisec timeout value can have the following values:
    •when millisec is 0, the function returns instantly.
    •when millisec is set to osWaitForever the function will wait for an infinite time until a message arrives.
    •all other values specify a time in millisecond for a timeout.

    www.keil.com/.../group___c_m_s_i_s___r_t_o_s___message.html

    Hope this helps

Reply
  • 0

    Yes there is a timeout value in the command according to the webpage

    osEvent osMessageGet ( osMessageQId queue_id, uint32_t millisec )

    Parameters
    [in] queue_id message queue ID obtained with osMessageCreate.
    [in] millisec timeout value or 0 in case of no time-out.
    Returnsevent information that includes status code. NoteMUST REMAIN UNCHANGED: osMessageGet shall be consistent in every CMSIS-RTOS.
    Suspend the execution of the current RUNNING thread until a message arrives. When a message is already in the queue, the function returns instantly with the message information.

    The argument millisec specifies how long the system waits for a message to become available. While the system waits the thread that is calling this function is put into the state WAITING. The millisec timeout value can have the following values:
    •when millisec is 0, the function returns instantly.
    •when millisec is set to osWaitForever the function will wait for an infinite time until a message arrives.
    •all other values specify a time in millisecond for a timeout.

    www.keil.com/.../group___c_m_s_i_s___r_t_o_s___message.html

    Hope this helps

Children
  • 0 in reply to Gary Olson

    Yes I knew that but I was looking a way to block the message pump when not needed to save the context switching of threads. This is part of a critical path in my application. Finally, I ended up add a flag in my message structure passed in parameter. I set this flag ON and send a message to this box for killing the message pump thread.

    Thank you for your response .