C Runtime for Lingua Franca
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sensor_simulator.h File Reference

Simple terminal-based user interface based on ncurses. More...

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int start_sensor_simulator (const char *message_lines[], int number_of_lines, int tick_window_width, char *log_file, int log_level)
void end_sensor_simulator ()
void show_tick (const char *character)
int register_sensor_key (char key, void *action)

Detailed Description

Simple terminal-based user interface based on ncurses.

Edward A. Lee

When prototyping Lingua Franca programs on a laptop, it is convenient to use the laptop keyboard to simulate asynchronous sensor input. This small library provides a convenient way to do that.

To use this, include the following flags in your target properties:

target C {
 files: [
 cmake-include: [

This requires ncurses, a library providing somewhat portable keyboard access.

In addition, you need this in your Lingua Franca file:

preamble {=
    include "sensor_simulator.c"

To start the sensor simulator, call start_sensor_simulator passing it an array of strings to print and the width of the window to use to display characters using the show_tick function.

To print messages to the screen, rather than using printf(), you should use the messaging functions in util.h, such as lf_print(). Otherwise, your messages will be printed over other information.

Function Documentation

◆ end_sensor_simulator()

void end_sensor_simulator ( )

End ncurses control of the terminal.

◆ register_sensor_key()

int register_sensor_key ( char key,
void * action )

Register a keyboard key to trigger the specified action. Printable ASCII characters (codes 32 to 127) are supported plus '
' and '\0', where the latter registers a trigger to invoked when any key is pressed. If a specific key is registered and any key ('\0') is also registered, the any key trigger will be scheduled after the specific key is scheduled. If these triggers belong to different reactors, they could be invoked in parallel. This will fail if the specified key has already been registered (error code 1), or the key is not a supported key or a newline ‘
’ or any key '\0' (error code 2) or if the trigger is NULL (error code 3).

keyThe key to register.
actionThe action to trigger when the key is pressed (a pointer to an lf_action_based_t struct).
0 for success, error code for failure.

◆ show_tick()

void show_tick ( const char * character)

Place a tick (usually a single character) in the tick window.

characterThe tick character.

◆ start_sensor_simulator()

int start_sensor_simulator ( const char * message_lines[],
int number_of_lines,
int tick_window_width,
char * log_file,
int log_level )

Start the sensor simulator if it has not been already started. This must be called at least once before any call to register_sensor_key. The specified message is an initial message to display at the upper left, typically a set of instructions, that remains displayed throughout the lifetime of the window. Please ensure that the message_lines array and its contained strings are not on the stack because they will be used later in a separate thread.

message_linesThe message lines.
number_of_linesThe number of lines.
tick_window_widthThe width of the tick window or 0 for none.
log_fileIf non-NULL, the name of a file to which to write logging messages.
log_levelThe level of log messages to redirect to the file. The level should be one of LOG_LEVEL_ERROR, LOG_LEVEL_WARNING, LOG_LEVEL_INFO, LOG_LEVEL_LOG, LOG_LEVEL_DEBUG, or LOG_LEVEL_ALL.
0 for success, error code for failure.