I'm running this java program on a raspberry pi. The program is supposed to run the script "hello_pixy" and scan what it prints out. When I run hello_pixy manually, it prints out lines normally (Via C's printf line). But when I run the program, nothing is printed out and the BufferedReader didn't read any lines.
If I substitute the script for something like "ls", then the BufferedReader reads it and prints it out. Is there a way I can change the "printf"s in C to send to the InputStream (I don't really know C, just enough from Java experience)?
Process process = null;
try {
process = Runtime.getRuntime().exec("sudo .ss/pixy/build/hello_pixy/hello_pixy");
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} //for Windows
try {
process.waitFor();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
BufferedReader reader = new BufferedReader(new InputStreamReader(process.getInputStream()));
String line;
String print = "";
try {
while ((line = reader.readLine()) != null) {
print += line;
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println("\nCodescan:\n\n" + print);
The code I'm executing is here: https://github.com/De-etz/pixy/blob/master/src/host/hello_pixy/hello_pixy.cpp
You're doing this back to front. You must read all the process's output first, and then call waitFor()
. Your way you will probably just deadlock, as the process can't exit until it has produced all its output, and if you're not reading it, it will eventually block.
Notes:
try
block must be inside that try
block. At present you are continuing after exceptions as though they didn't happen. Don't write code like this.