Scripting 8.1. The sendpraat subroutine

Scripting 8.1. The sendpraat subroutine

Sendpraat can be a subroutine for sending messages to a running Praat program.

C syntax

   sendpraat7 (long timeOut, int fullTrust, const char *program, char *text);

Arguments

timeOut (MacOS and Linux only): the number of seconds that sendpraat will wait for an answer before writing an error message. A timeOut of 0 means that the message will be sent asynchronously, i.e., that sendpraat will return immediately without issuing any error message.
fullTrust: a boolean (0 or 1) that determines whether the script should be allowed to save files and call system commands (1), or not (0).
program: the name of a running program that uses the Praat shell, e.g. "Praat". The first letter may be specified as lower or upper case; it will be converted to upper case for Windows or MacOS and to lower case for Linux.
text: the script text to be sent. Sendpraat may alter this text!

Example 1: killing a program

   char message [100], *errorMessage;

   strcpy (message, "Quit");

   errorMessage = sendpraat7 (0, 0, "praat", message);

   if (errorMessage) fprintf (stderr, "%s", errorMessage);

This causes the program Praat to quit (gracefully), because Quit is a fixed command in one of the menus of that program. On MacOS and Linux, sendpraat returns immediately; on Windows, the timeOut argument is ignored. The return value errorMessage is a statically allocated string internal to sendpraat, and is overwritten by the next call to sendpraat.

Example 2: playing a sound file in reverse

Suppose you have a sound file whose name is in the variable fileName, and you want the program Praat, which can play sounds, to play this sound backwards.

   char message [1000], *errorMessage;

   snprintf (message,1000, "Read from file: ~%s\nPlay reverse\nRemove", fileName);

   errorMessage = sendpraat7 (3000, 0, "praat", message);

This will work because Play reverse is an action command that becomes available in the dynamic menu when a Sound is selected. On Linux, sendpraat will allow Praat at most 3000 seconds to perform this.

Example 3: executing a large script file

Sometimes, it may be unpractical to send a large script directly to sendpraat. Fortunately, the receiving program knows runScript:

   char message [100], *errorMessage;

   strcpy (message, "runScript: \"doAll.praat\", 20");

   errorMessage = sendpraat7 (0, 1, "praat", message);

This causes the program Praat to run the script doAll.praat with an argument of "20".

How to download

You can download the source code of the sendpraat subroutine via https://praat.org/sendpraat.html or from https://www.fon.hum.uva.nl/praat/sendpraat.html.

Instead

Instead of using sendpraat, you can also just take the following simple steps in your program:

1. on Linux, write the Praat script that you want to run, and save it as ~/.config/Message.txt;

2. get Praat's process id from ~/.config/pid;

3. if Praat's process id is e.g. 1178, send it a SIGUSR1 signal: kill -USR1 1178

If the first line of your script is the comment “# 999”, where 999 stands for the process id of your program, Praat will send your program a SIGUSR2 signal back when it finishes handling the script. If you do not want to receive such a message (if your program has no handler for it, the SIGUSR2 signal will kill your program), then do not include such a line.

If the second line of your script is “# --FULL-TRUST”