linux - Pass param to USB ioctl -
i have problem read/write data usb mass storage device, 'device or resource busy' error below command: ioctl(usbfd, usbdevfs_claiminterface, &interface_num) so need release interface before. don't know how can pass interface_num correctly command: ioctl(usbfd, usbdevfs_releaseinterface, &interface_num), if it's not defined, there function found interface number. please me! thanks. the documentation states: usbdevfs_releaseinterface this used release claim usbfs made on interface, either implicitly or because of usbdevfs_claiminterface call, before file descriptor closed. ioctl parameter integer holding number of interface ( binterfacenumber descriptor); file modification time not updated request. but seems here "parameter integer" still means pointer integer should passed, you're showing. if have descriptor, can find interface number.