running BASH commands from C++

[Dhanushka Jayaweera]

hey guys,

I want to add this bash command to my c++ program. 

echo cape-bone-iio > /sys/devices/bone_capemgr.*/slots

i tried this

#include<cstdio>

#include<cstdlib>

#include<unistd.h>

using namespace std;

int main() {

    system("echo cape-bone-iio > /sys/devices/bone_capemgr.*/slots");

    return 0;

}

but it does not work. 

Can someone help me with this?

[Bas Laarhoven]

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Have you verified that the system command does wildcard expansion?
(Replace the asterisk in the command by the proper number and verify whether that works)

-- Bas

[Dhanushka Jayaweera]

well i tried this 

system("echo cape-bone-iio > /sys/devices/bone_capemgr.9/slots");

still the same

[Dhanushka Jayaweera]

both commands work in the terminal

[Bas Laarhoven]

On 21-12-2013 17:24, Dhanushka Jayaweera wrote:

both commands work in the terminal

So you know what to do, now find out how to do it :-)
What is the result from the system() call?

-- Bas

BTW: You can also try writing the proper text directly to the slots file!

[Dhanushka Jayaweera]

im getting nothing.. no errors. but it wont write the file either  :(

im pretty new to BBB, its just my 5th day of using it... and I did some googling, couldn't find a solution yet..

im using  "echo cape-bone-iio > /sys/devices/bone_capemgr.9/slots"  to create the file for ADC. right now i have to execute the bash command manually before i execute the c++ file which I wrote to read ADC values

Btw what is  "writing the proper text directly to the slots file" ?? im kinda lost 

[David Lambert]

Have you tried looking at the return status of the "system" call. That may give a clue. Also it may be worth explicitly giving the path for echo:

int status;
status =  system("/bin/echo cape-bone-iio > /sys/devices/bone_capemgr.9/slots");
printf("status = %d\n", status);


HTH,

Dave.

[Dhanushka Jayaweera]

hey guys,

system("/bin/echo cape-bone-iio > /sys/devices/bone_capemgr.9/slots");   -   works 

I simply forgot a header file :/

#include <fstream>  //has to be in the code