[SOLVED] C++ how to get a string parameter from another program with '|' or < in bash

embeddedPROJECTS · 11-09-2013, 07:30 PM

I wrote a program that writes data on an lcd display of my Raspberry pi, but it only gets data typed on the terminal, if i write 'uname -r | lcd_message' it doesnt write anything.

I used the standard code:

int main(int argc, char *argv[])....and so on.

sag47 · 11-10-2013, 01:00 PM

You'll want to look up "C stdin" or "C++ stdin". From the bash man page when you're using a pipe you're redirecting stdout of one program to stdin of another. In a program the three most common file descriptors are stdout (file descriptor 1), stdin (file descriptor 0), and stderr (file descriptor 2). However, a program can have up to 9 file descriptors to manipulate input and output.

See Redirection in bash for a more thorough description about that topic.

embeddedPROJECTS · 11-10-2013, 04:44 PM

Cool, thanks sag47, now i know where to look.