ioctl call on /dev/ttyGS0 return errno25

[Saurabh Jain]

Dear developers,

I am trying to run follwing code to open and get info about "/dev/ttyGS0" port in BBB

#include <linux/serial.h>

bool foo()
{
    const mode_t flags = O_RDWR | O_NONBLOCK | O_NOCTTY;
    const int fd = ::open("/dev/ttyGS0", flags);
    if (fd != -1) {
        struct serial_struct serinfo;
        const int retval = ::ioctl(fd, TIOCGSERIAL, &serinfo);
        ::close(fd);
        if (retval != -1 && serinfo.type != PORT_UNKNOWN)
            return true;
    }
    return false;
}

But I am getting "retval = -1" when following statement is run

 const int retval = ::ioctl(fd, TIOCGSERIAL, &serinfo);

On further analysis I found that ioctl function call, return errno 25.

Can you please inform me what can be the reason for this error and how can i solve it.

Please inform me if you need any other information from me.


Many thanks


Regards

Saurabh Jain