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The Message Publisher publishes executive and/or model messages. A Message Subscriber gets the messages published by the Publisher.
Message Publisher
Trick creates one instance of the Message Publisher (in the S_define file). It is responsible for keeping track of all Message Subscribers,
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
::message_subscribe routine (and conversely can be removed from the publisher by calling ::message_unsubscribe).
Publishing a message that you want to be output by all subscribers is done by calling ::message_publish.
If there are no subscribers, then publishing a message has no effect.
Message Subscriber
There can be any number of Message Subscribers, whose job is to receive (and usually output) published messages. Trick automatically creates three Message Subscribers:
Trick::MessageCout- outputs messages with level < 100 to the standard output streamTrick::MessageHSFile- outputs messages with level < 100 to a file namedsend_hsin the RUN directoryTrick::MessageTCDevice- outputs messages with level < 100 to a socket at port 7200, used by the Simulation Control Panel for its Status Messages display
When you publish a message, it will be output by the three subscribers above.
A subscriber can be enabled / disabled at any time during simulation execution to output / ignore messages as desired.
The user may also add their own subscriber by creating a derived class from Trick::MessageSubscriber.
Trick::MessageThreadedCout- outputs messages to the standard output stream asynchronously.
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.
To activate the MessageThreadedCout class, there are two ways:
- Add these 2 lines to the input file:
trick_message.mtcout.init()
trick.message_subscribe(trick_message.mtcout)
- Or add this line to the input file:
trick_message.separate_thread_set_enabled(True)
trick_message.separate_thread_set_enabled(True) - turns on outputting messages to the standard output stream on a separate thread while turning off outputting messages to the standard output stream on the same thread and Sim Control Panel
trick_message.separate_thread_set_enabled(False) - turns off outputting messages to the standard output stream on a separate thread while turning on outputing messages to the standard output stream on the same thread and Sim Control Panel
Publish a message
To publish a message:
#include "trick/message_proto.h"
#include "trick/message_level.h"
int message_publish(int level, const char * format_msg, ...) ;
The level number can be any number greater than or equal to 0. Levels 0-99 are captured by Trick's default message subscribers. Trick has a few predefined levels (Trick::MessagePublisher::MESSAGE_TYPE) that it uses for publishing messages.
If the message subscriber's color is enabled (see below), then a particular colored message will be displayed for each of these levels:
- 0 - normal message, default color
- 1 - informational message, green
- 2 - warning message, yellow
- 3 - error message, red
- 10 - debug message, cyan
Open a custom log file
To open a custom message file:
#include "trick/Message_proto.hh"
int open_custom_message_file(std::string file_name, std::string subscriber_name, int level = -1);
This function opens a new file, adds it to the list of message subscribers, and returns the level that can be used to write to the file.
A user can specify a level >= 0. If open_custom_message_file is called without a level argument, the function will assign a unique level to the file that is >= 100. If a user wants the messages written to this file to also be captured by default Trick message subscribers, they should specify a level from 0-99.
Example:
// Open the logfile
int my_level = open_custom_message_file("my_log_dir/logfile", "custom_log");
// Write to it by publishing a message with the given level
message_publish(my_level, "This message will be written to my custom logfile");
User accessible routines
To subscribe / unsubscribe Trick's default subscribers (these call ::message_subscribe / ::message_unsubscribe mentioned above):
By default these are all subscribed. You can use subscribe/unsubscribe throughout a simulation to turn on/off messages at will.
trick.message_unsubscribe(trick_message.mcout)
trick.message_unsubscribe(trick_message.mdevice)
trick.message_unsubscribe(trick_message.mfile)
To enable / disable Trick's default subscribers:
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.
That means you cannot then later try to enable and subscribe to file/device.
int set_enabled(bool yes_no)
trick_message.mcout.set_enabled(bool yes_no);
trick_message.mdevice.set_enabled(bool yes_no);
trick_message.mfile.set_enabled(bool yes_no);
To enable / disable showing colored messages in Trick's default subscribers:
By default color is enabled for cout and device. Color is achieved by adding ANSI escape codes around the message.
int set_color(bool yes_no)
trick_message.mcout.set_color(bool yes_no);
trick_message.mdevice.set_color(bool yes_no);
trick_message.mfile.set_color(bool yes_no);