usb_test.c

//usb_test.c
//compile: gcc usb_test.c -o usb_test

#include <fcntl.h>          /* O_RDWR  */
#include <stdio.h>
#include <unistd.h>
#include <string.h>


void open_port(char * portname) {

    int fd;

    printf("opening [%s]\n", portname);
    fd = open(portname, O_RDWR);
    if(fd == -1) {
        printf("failed\n");
        return;
    }
    printf("ok\n");
    sleep(5);

}

int main() {
    printf("idle \n");

    open_port("/dev/ttyUSB0");
    open_port("/dev/ttyUSB1");
    open_port("/dev/ttyUSB2");
    open_port("/dev/ttyUSB3");
    open_port("/dev/ttyUSB4");
    open_port("/dev/ttyUSB5");
    open_port("/dev/ttyUSB6");
    open_port("/dev/ttyUSB7");
    open_port("/dev/ttyUSB8");

    printf("idle 2\n");
}