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84 lines
3.9 KiB
Markdown
84 lines
3.9 KiB
Markdown
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The Message Publisher publishes executive and/or model messages. A Message Subscriber gets the messages published by the Publisher.
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### Message Publisher
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Trick creates one instance of the Message Publisher (in the `S_define` file). It is responsible for keeping track of all Message Subscribers,
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and sending any message that is published to all of the Message Subscribers. A subscriber is made known to the Message Publisher by calling its
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`::message_subscribe` routine (and conversely can be removed from the publisher by calling `::message_unsubscribe`).
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Publishing a message that you want to be output by all subscribers is done by calling `::message_publish`.
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If there are no subscribers, then publishing a message has no effect.
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### Message Subscriber
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There can be any number of Message Subscribers, whose job is to receive (and usually output) published messages. Trick automatically creates three Message Subscribers:
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- `Trick::MessageCout` - outputs messages to the standard output stream
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- `Trick::MessageFile` - outputs messages to a file named `send_hs` in the RUN directory
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- `Trick::MessageTCDevice` - outputs messages to a socket at port 7200, used by the Simulation Control Panel for its Status Messages display
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When you publish a message, it will be output by the three subscribers above.
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A subscriber can be enabled / disabled at any time during simulation execution to output / ignore messages as desired.
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The user may also add their own subscriber by creating a derived class from `Trick::MessageSubscriber`.
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- `Trick::MessageThreadedCout` - outputs messages to the standard output stream asynchronously.
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The `MessageThreadedCout` class is included with the simulation but not activated by default. When activated messages will be written to the standard output stream like `MessageCout`, but internally we use a separate thread to do the writing. This helps real-time performance.
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To activate the `MessageThreadedCout` class, add these 2 lines to the input file.
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```python
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trick_message.mtcout.init()
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trick.message_subscribe(trick_message.mtcout)
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```
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### User accessible routines
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To publish a message:
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```cpp
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int ::message_publish(int level, const char * format_msg, ...) ;
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int ::send_hs(FILE * fp, const char * format_msg, ...) ;
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```
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The level number can be any integer from 0 to 99. Trick has a few predefined levels (`Trick::MessagePublisher::MESSAGE_TYPE`) that it uses for publishing messages.
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If the message subscriber's color is enabled (see below), then a particular colored message will be displayed for each of these levels:
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- 0 - normal message, default color
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- 1 - informational message, green
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- 2 - warning message, yellow
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- 3 - error message, red
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- 10 - debug message, cyan
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To subscribe / unsubscribe Trick's default subscribers (these call `::message_subscribe` / `::message_unsubscribe` mentioned above):
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By default these are all subscribed. You can use subscribe/unsubscribe throughout a simulation to turn on/off messages at will.
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```python
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trick.message_unsubscribe(trick_message.mcout)
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trick.message_unsubscribe(trick_message.mdevice)
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trick.message_unsubscribe(trick_message.mfile)
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```
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To enable / disable Trick's default subscribers:
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By default these are all enabled. If you disable `file` at startup, the `send_hs` file will not be created/opened. If you disable `device` at startup, its connection will not be established.
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That means you cannot then later try to enable and subscribe to file/device.
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```cpp
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int message_cout_set_enabled(int yes_no) ;
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int message_file_set_enabled(int yes_no) ;
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int message_device_set_enabled(int yes_no) ;
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```
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To enable / disable showing colored messages in Trick's default subscribers:
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By default color is enabled for `cout` and `device`. Color is achieved by adding ANSI escape codes around the message.
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```cpp
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int message_cout_set_color(int yes_no) ;
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int message_file_set_color(int yes_no) ;
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int message_device_set_color(int yes_no) ;
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```
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[Continue to Command Line Arguments](Command-Line-Arguments)
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