diff --git a/device/device.go b/device/device.go index ef7f2be..21ee7ab 100644 --- a/device/device.go +++ b/device/device.go @@ -80,9 +80,7 @@ func Open(path string, options ...Option) (*Device, error) { } // ensures IOType is set, only MemMap supported now - //if reflect.ValueOf(dev.config.ioType).IsZero() { dev.config.ioType = v4l2.IOTypeMMAP - //} // reset crop, only if cropping supported if cropcap, err := v4l2.GetCropCapability(dev.fd, dev.bufType); err == nil { @@ -425,19 +423,3 @@ func (d *Device) startStreamLoop(ctx context.Context) error { return nil } - -// prepareCaptureBuffer prepares a frame buffer for stream capture -func (d *Device) prepareCaptureBuffer(fd uintptr, ioType v4l2.IOType, bufType v4l2.BufType) (v4l2.Buffer, error) { - bufInfo, err := v4l2.DequeueBuffer(fd, ioType, bufType) - if err != nil { - return v4l2.Buffer{}, fmt.Errorf("capture buffer info: dequeue: %w", err) - } - - // requeue/clear used buffer, prepare for next read - if _, err := v4l2.QueueBuffer(fd, ioType, bufType, bufInfo.Index); err != nil { - return v4l2.Buffer{}, fmt.Errorf("capture buffer info: queue: %w", err) - } - - // return captured buffer info - return bufInfo, nil -} diff --git a/examples/ccapture/README.md b/examples/ccapture/README.md new file mode 100644 index 0000000..a216b9b --- /dev/null +++ b/examples/ccapture/README.md @@ -0,0 +1,30 @@ +# V4L2 video capture example in C + +This an example in C showing a minimally required steps to capture video using V4L2. This is can be used to run tests on devices and compare results with the Go4VL code. + +## Build and run +On a Linux machine, run the following: + +``` +gcc -o capture capture.c +``` + +Run the program using: + +``` +./capture +``` + +Or, run `--help` to see available flags: + +``` +./capture --help +``` + +## Debugging with `strace` + +To view the ioctl calls made when running the capture program: + +``` +strace -o trace.log -e trace=ioctl ./capture +``` \ No newline at end of file diff --git a/examples/ccapture/capture-minimal.c b/examples/ccapture/capture-minimal.c deleted file mode 100644 index 3156635..0000000 --- a/examples/ccapture/capture-minimal.c +++ /dev/null @@ -1,434 +0,0 @@ -/* - * V4L2 video capture example - * Used to validate result from test devices. - * Based on https://git.linuxtv.org/v4l-utils.git/ - */ - -#include -#include -#include -#include - -#include /* getopt_long() */ - -#include /* low-level i/o */ -#include -#include -#include -#include -#include -#include -#include - -#include - -#define CLEAR(x) memset(&(x), 0, sizeof(x)) - -enum io_method { - IO_METHOD_MMAP, -}; - -struct buffer { - void *start; - size_t length; -}; - -static char *dev_name; -static enum io_method io = IO_METHOD_MMAP; -static int fd = -1; -struct buffer *buffers; -static unsigned int n_buffers; -static int out_buf; -static int force_format; -static int frame_count = 70; - -static void errno_exit(const char *s) -{ - fprintf(stderr, "%s error %d, %s\n", s, errno, strerror(errno)); - exit(EXIT_FAILURE); -} - -static int xioctl(int fh, unsigned long int request, void *arg) -{ - int r; - - do { - r = ioctl(fh, request, arg); - } while (-1 == r && EINTR == errno); - - return r; -} - -static void process_image(const void *p, int size) -{ - if (out_buf) - fwrite(p, size, 1, stdout); - - fflush(stderr); - fprintf(stderr, "."); - fflush(stdout); -} - -static int read_frame(void) -{ - struct v4l2_buffer buf; - unsigned int i; - - CLEAR(buf); - - buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; - buf.memory = V4L2_MEMORY_MMAP; - - if (-1 == xioctl(fd, VIDIOC_DQBUF, &buf)) { - switch (errno) { - case EAGAIN: - return 0; - - case EIO: - /* Could ignore EIO, see spec. */ - - /* fall through */ - - default: - errno_exit("VIDIOC_DQBUF"); - } - } - - assert(buf.index < n_buffers); - - process_image(buffers[buf.index].start, buf.bytesused); - - if (-1 == xioctl(fd, VIDIOC_QBUF, &buf)) - errno_exit("VIDIOC_QBUF"); - - return 1; -} - -static void mainloop(void) -{ - unsigned int count; - - count = frame_count; - - while (count-- > 0) { - for (;;) { - fd_set fds; - struct timeval tv; - int r; - - FD_ZERO(&fds); - FD_SET(fd, &fds); - - /* Timeout. */ - tv.tv_sec = 2; - tv.tv_usec = 0; - - r = select(fd + 1, &fds, NULL, NULL, &tv); - - if (-1 == r) { - if (EINTR == errno) - continue; - errno_exit("select"); - } - - if (0 == r) { - fprintf(stderr, "select timeout\n"); - exit(EXIT_FAILURE); - } - - if (read_frame()) - break; - /* EAGAIN - continue select loop. */ - } - } -} - -static void stop_capturing(void) -{ - enum v4l2_buf_type type; - - type = V4L2_BUF_TYPE_VIDEO_CAPTURE; - if (-1 == xioctl(fd, VIDIOC_STREAMOFF, &type)) - errno_exit("VIDIOC_STREAMOFF"); - -} - -static void start_capturing(void) -{ - unsigned int i; - enum v4l2_buf_type type; - - - for (i = 0; i < n_buffers; ++i) { - struct v4l2_buffer buf; - - CLEAR(buf); - buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; - buf.memory = V4L2_MEMORY_MMAP; - buf.index = i; - - if (-1 == xioctl(fd, VIDIOC_QBUF, &buf)) - errno_exit("VIDIOC_QBUF"); - } - type = V4L2_BUF_TYPE_VIDEO_CAPTURE; - if (-1 == xioctl(fd, VIDIOC_STREAMON, &type)) - errno_exit("VIDIOC_STREAMON"); - -} - -static void uninit_device(void) -{ - unsigned int i; - for (i = 0; i < n_buffers; ++i) - if (-1 == munmap(buffers[i].start, buffers[i].length)) - errno_exit("munmap"); - - free(buffers); -} - -static void init_mmap(void) -{ - struct v4l2_requestbuffers req; - - CLEAR(req); - - req.count = 4; - req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; - req.memory = V4L2_MEMORY_MMAP; - - if (-1 == xioctl(fd, VIDIOC_REQBUFS, &req)) { - if (EINVAL == errno) { - fprintf(stderr, "%s does not support " - "memory mapping\n", dev_name); - exit(EXIT_FAILURE); - } else { - errno_exit("VIDIOC_REQBUFS"); - } - } - - if (req.count < 2) { - fprintf(stderr, "Insufficient buffer memory on %s\n", - dev_name); - exit(EXIT_FAILURE); - } - - buffers = calloc(req.count, sizeof(*buffers)); - - if (!buffers) { - fprintf(stderr, "Out of memory\n"); - exit(EXIT_FAILURE); - } - - for (n_buffers = 0; n_buffers < req.count; ++n_buffers) { - struct v4l2_buffer buf; - - CLEAR(buf); - - buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; - buf.memory = V4L2_MEMORY_MMAP; - buf.index = n_buffers; - - if (-1 == xioctl(fd, VIDIOC_QUERYBUF, &buf)) - errno_exit("VIDIOC_QUERYBUF"); - - buffers[n_buffers].length = buf.length; - buffers[n_buffers].start = - mmap(NULL /* start anywhere */, - buf.length, - PROT_READ | PROT_WRITE /* required */, - MAP_SHARED /* recommended */, - fd, buf.m.offset); - - if (MAP_FAILED == buffers[n_buffers].start) - errno_exit("mmap"); - } -} - -static void init_device(void) -{ - struct v4l2_capability cap; - struct v4l2_cropcap cropcap; - struct v4l2_crop crop; - struct v4l2_format fmt; - - if (-1 == xioctl(fd, VIDIOC_QUERYCAP, &cap)) { - if (EINVAL == errno) { - fprintf(stderr, "%s is no V4L2 device\n", - dev_name); - exit(EXIT_FAILURE); - } else { - errno_exit("VIDIOC_QUERYCAP"); - } - } - - if (!(cap.capabilities & V4L2_CAP_VIDEO_CAPTURE)) { - fprintf(stderr, "%s is no video capture device\n", - dev_name); - exit(EXIT_FAILURE); - } - - if (!(cap.capabilities & V4L2_CAP_STREAMING)) { - fprintf(stderr, "%s does not support streaming i/o\n", dev_name); - exit(EXIT_FAILURE); - } - - - /* Select video input, video standard and tune here. */ - CLEAR(cropcap); - - cropcap.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; - - if (0 == xioctl(fd, VIDIOC_CROPCAP, &cropcap)) { - crop.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; - crop.c = cropcap.defrect; /* reset to default */ - - if (-1 == xioctl(fd, VIDIOC_S_CROP, &crop)) { - switch (errno) { - case EINVAL: - /* Cropping not supported. */ - break; - default: - /* Errors ignored. */ - break; - } - } - } else { - /* Errors ignored. */ - } - - - CLEAR(fmt); - - fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; - if (force_format) { - fmt.fmt.pix.width = 640; - fmt.fmt.pix.height = 480; - fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV; - fmt.fmt.pix.field = V4L2_FIELD_INTERLACED; - - if (-1 == xioctl(fd, VIDIOC_S_FMT, &fmt)) - errno_exit("VIDIOC_S_FMT"); - - /* Note VIDIOC_S_FMT may change width and height. */ - } else { - /* Preserve original settings as set by v4l2-ctl for example */ - if (-1 == xioctl(fd, VIDIOC_G_FMT, &fmt)) - errno_exit("VIDIOC_G_FMT"); - } - - init_mmap(); -} - -static void close_device(void) -{ - if (-1 == close(fd)) - errno_exit("close"); - - fd = -1; -} - -static void open_device(void) -{ - struct stat st; - - if (-1 == stat(dev_name, &st)) { - fprintf(stderr, "Cannot identify '%s': %d, %s\n", - dev_name, errno, strerror(errno)); - exit(EXIT_FAILURE); - } - - if (!S_ISCHR(st.st_mode)) { - fprintf(stderr, "%s is no device\n", dev_name); - exit(EXIT_FAILURE); - } - - fd = open(dev_name, O_RDWR /* required */ | O_NONBLOCK, 0); - - if (-1 == fd) { - fprintf(stderr, "Cannot open '%s': %d, %s\n", - dev_name, errno, strerror(errno)); - exit(EXIT_FAILURE); - } -} - -static void usage(FILE *fp, int argc, char **argv) -{ - fprintf(fp, - "Usage: %s [options]\n\n" - "Version 1.3\n" - "Options:\n" - "-d | --device name Video device name [%s]\n" - "-h | --help Print this message\n" - "-o | --output Outputs stream to stdout\n" - "-f | --format Force format to 640x480 YUYV\n" - "-c | --count Number of frames to grab [%i]\n" - "", - argv[0], dev_name, frame_count); -} - -static const char short_options[] = "d:hmruofc:"; - -static const struct option -long_options[] = { - { "device", required_argument, NULL, 'd' }, - { "help", no_argument, NULL, 'h' }, - { "mmap", no_argument, NULL, 'm' }, - { "output", no_argument, NULL, 'o' }, - { "format", no_argument, NULL, 'f' }, - { "count", required_argument, NULL, 'c' }, - { 0, 0, 0, 0 } -}; - -int main(int argc, char **argv) -{ - dev_name = "/dev/video0"; - - for (;;) { - int idx; - int c; - - c = getopt_long(argc, argv, - short_options, long_options, &idx); - - if (-1 == c) - break; - - switch (c) { - case 0: /* getopt_long() flag */ - break; - - case 'd': - dev_name = optarg; - break; - - case 'h': - usage(stdout, argc, argv); - exit(EXIT_SUCCESS); - - case 'o': - out_buf++; - break; - - case 'c': - errno = 0; - frame_count = strtol(optarg, NULL, 0); - if (errno) - errno_exit(optarg); - break; - - default: - usage(stderr, argc, argv); - exit(EXIT_FAILURE); - } - } - - open_device(); - init_device(); - start_capturing(); - mainloop(); - stop_capturing(); - uninit_device(); - close_device(); - fprintf(stderr, "\n"); - return 0; -} \ No newline at end of file diff --git a/examples/ccapture/capture.c b/examples/ccapture/capture.c index 66c9100..3156635 100644 --- a/examples/ccapture/capture.c +++ b/examples/ccapture/capture.c @@ -25,9 +25,7 @@ #define CLEAR(x) memset(&(x), 0, sizeof(x)) enum io_method { - IO_METHOD_READ, IO_METHOD_MMAP, - IO_METHOD_USERPTR, }; struct buffer { @@ -76,27 +74,6 @@ static int read_frame(void) struct v4l2_buffer buf; unsigned int i; - switch (io) { - case IO_METHOD_READ: - if (-1 == read(fd, buffers[0].start, buffers[0].length)) { - switch (errno) { - case EAGAIN: - return 0; - - case EIO: - /* Could ignore EIO, see spec. */ - - /* fall through */ - - default: - errno_exit("read"); - } - } - - process_image(buffers[0].start, buffers[0].length); - break; - - case IO_METHOD_MMAP: CLEAR(buf); buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; @@ -123,42 +100,6 @@ static int read_frame(void) if (-1 == xioctl(fd, VIDIOC_QBUF, &buf)) errno_exit("VIDIOC_QBUF"); - break; - - case IO_METHOD_USERPTR: - CLEAR(buf); - - buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; - buf.memory = V4L2_MEMORY_USERPTR; - - if (-1 == xioctl(fd, VIDIOC_DQBUF, &buf)) { - switch (errno) { - case EAGAIN: - return 0; - - case EIO: - /* Could ignore EIO, see spec. */ - - /* fall through */ - - default: - errno_exit("VIDIOC_DQBUF"); - } - } - - for (i = 0; i < n_buffers; ++i) - if (buf.m.userptr == (unsigned long)buffers[i].start - && buf.length == buffers[i].length) - break; - - assert(i < n_buffers); - - process_image((void *)buf.m.userptr, buf.bytesused); - - if (-1 == xioctl(fd, VIDIOC_QBUF, &buf)) - errno_exit("VIDIOC_QBUF"); - break; - } return 1; } @@ -206,18 +147,10 @@ static void stop_capturing(void) { enum v4l2_buf_type type; - switch (io) { - case IO_METHOD_READ: - /* Nothing to do. */ - break; + type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + if (-1 == xioctl(fd, VIDIOC_STREAMOFF, &type)) + errno_exit("VIDIOC_STREAMOFF"); - case IO_METHOD_MMAP: - case IO_METHOD_USERPTR: - type = V4L2_BUF_TYPE_VIDEO_CAPTURE; - if (-1 == xioctl(fd, VIDIOC_STREAMOFF, &type)) - errno_exit("VIDIOC_STREAMOFF"); - break; - } } static void start_capturing(void) @@ -225,91 +158,34 @@ static void start_capturing(void) unsigned int i; enum v4l2_buf_type type; - switch (io) { - case IO_METHOD_READ: - /* Nothing to do. */ - break; - case IO_METHOD_MMAP: - for (i = 0; i < n_buffers; ++i) { - struct v4l2_buffer buf; + for (i = 0; i < n_buffers; ++i) { + struct v4l2_buffer buf; - CLEAR(buf); - buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; - buf.memory = V4L2_MEMORY_MMAP; - buf.index = i; + CLEAR(buf); + buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + buf.memory = V4L2_MEMORY_MMAP; + buf.index = i; - if (-1 == xioctl(fd, VIDIOC_QBUF, &buf)) - errno_exit("VIDIOC_QBUF"); - } + if (-1 == xioctl(fd, VIDIOC_QBUF, &buf)) + errno_exit("VIDIOC_QBUF"); + } type = V4L2_BUF_TYPE_VIDEO_CAPTURE; if (-1 == xioctl(fd, VIDIOC_STREAMON, &type)) errno_exit("VIDIOC_STREAMON"); - break; - - case IO_METHOD_USERPTR: - for (i = 0; i < n_buffers; ++i) { - struct v4l2_buffer buf; - CLEAR(buf); - buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; - buf.memory = V4L2_MEMORY_USERPTR; - buf.index = i; - buf.m.userptr = (unsigned long)buffers[i].start; - buf.length = buffers[i].length; - - if (-1 == xioctl(fd, VIDIOC_QBUF, &buf)) - errno_exit("VIDIOC_QBUF"); - } - type = V4L2_BUF_TYPE_VIDEO_CAPTURE; - if (-1 == xioctl(fd, VIDIOC_STREAMON, &type)) - errno_exit("VIDIOC_STREAMON"); - break; - } } static void uninit_device(void) { unsigned int i; - - switch (io) { - case IO_METHOD_READ: - free(buffers[0].start); - break; - - case IO_METHOD_MMAP: - for (i = 0; i < n_buffers; ++i) - if (-1 == munmap(buffers[i].start, buffers[i].length)) - errno_exit("munmap"); - break; - - case IO_METHOD_USERPTR: - for (i = 0; i < n_buffers; ++i) - free(buffers[i].start); - break; - } + for (i = 0; i < n_buffers; ++i) + if (-1 == munmap(buffers[i].start, buffers[i].length)) + errno_exit("munmap"); free(buffers); } -static void init_read(unsigned int buffer_size) -{ - buffers = calloc(1, sizeof(*buffers)); - - if (!buffers) { - fprintf(stderr, "Out of memory\n"); - exit(EXIT_FAILURE); - } - - buffers[0].length = buffer_size; - buffers[0].start = malloc(buffer_size); - - if (!buffers[0].start) { - fprintf(stderr, "Out of memory\n"); - exit(EXIT_FAILURE); - } -} - static void init_mmap(void) { struct v4l2_requestbuffers req; @@ -368,44 +244,6 @@ static void init_mmap(void) } } -static void init_userp(unsigned int buffer_size) -{ - struct v4l2_requestbuffers req; - - CLEAR(req); - - req.count = 4; - req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; - req.memory = V4L2_MEMORY_USERPTR; - - if (-1 == xioctl(fd, VIDIOC_REQBUFS, &req)) { - if (EINVAL == errno) { - fprintf(stderr, "%s does not support " - "user pointer i/o\n", dev_name); - exit(EXIT_FAILURE); - } else { - errno_exit("VIDIOC_REQBUFS"); - } - } - - buffers = calloc(4, sizeof(*buffers)); - - if (!buffers) { - fprintf(stderr, "Out of memory\n"); - exit(EXIT_FAILURE); - } - - for (n_buffers = 0; n_buffers < 4; ++n_buffers) { - buffers[n_buffers].length = buffer_size; - buffers[n_buffers].start = malloc(buffer_size); - - if (!buffers[n_buffers].start) { - fprintf(stderr, "Out of memory\n"); - exit(EXIT_FAILURE); - } - } -} - static void init_device(void) { struct v4l2_capability cap; @@ -429,29 +267,13 @@ static void init_device(void) exit(EXIT_FAILURE); } - switch (io) { - case IO_METHOD_READ: - if (!(cap.capabilities & V4L2_CAP_READWRITE)) { - fprintf(stderr, "%s does not support read i/o\n", - dev_name); - exit(EXIT_FAILURE); - } - break; - - case IO_METHOD_MMAP: - case IO_METHOD_USERPTR: - if (!(cap.capabilities & V4L2_CAP_STREAMING)) { - fprintf(stderr, "%s does not support streaming i/o\n", - dev_name); - exit(EXIT_FAILURE); - } - break; + if (!(cap.capabilities & V4L2_CAP_STREAMING)) { + fprintf(stderr, "%s does not support streaming i/o\n", dev_name); + exit(EXIT_FAILURE); } /* Select video input, video standard and tune here. */ - - CLEAR(cropcap); cropcap.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; @@ -494,19 +316,7 @@ static void init_device(void) errno_exit("VIDIOC_G_FMT"); } - switch (io) { - case IO_METHOD_READ: - init_read(fmt.fmt.pix.sizeimage); - break; - - case IO_METHOD_MMAP: - init_mmap(); - break; - - case IO_METHOD_USERPTR: - init_userp(fmt.fmt.pix.sizeimage); - break; - } + init_mmap(); } static void close_device(void) @@ -549,9 +359,6 @@ static void usage(FILE *fp, int argc, char **argv) "Options:\n" "-d | --device name Video device name [%s]\n" "-h | --help Print this message\n" - "-m | --mmap Use memory mapped buffers [default]\n" - "-r | --read Use read() calls\n" - "-u | --userp Use application allocated buffers\n" "-o | --output Outputs stream to stdout\n" "-f | --format Force format to 640x480 YUYV\n" "-c | --count Number of frames to grab [%i]\n" @@ -566,8 +373,6 @@ long_options[] = { { "device", required_argument, NULL, 'd' }, { "help", no_argument, NULL, 'h' }, { "mmap", no_argument, NULL, 'm' }, - { "read", no_argument, NULL, 'r' }, - { "userp", no_argument, NULL, 'u' }, { "output", no_argument, NULL, 'o' }, { "format", no_argument, NULL, 'f' }, { "count", required_argument, NULL, 'c' }, @@ -600,26 +405,10 @@ int main(int argc, char **argv) usage(stdout, argc, argv); exit(EXIT_SUCCESS); - case 'm': - io = IO_METHOD_MMAP; - break; - - case 'r': - io = IO_METHOD_READ; - break; - - case 'u': - io = IO_METHOD_USERPTR; - break; - case 'o': out_buf++; break; - case 'f': - force_format++; - break; - case 'c': errno = 0; frame_count = strtol(optarg, NULL, 0); diff --git a/v4l2/syscalls.go b/v4l2/syscalls.go index 67fc2bb..5b0d33d 100644 --- a/v4l2/syscalls.go +++ b/v4l2/syscalls.go @@ -5,11 +5,12 @@ import ( "fmt" "io/fs" "os" - "unsafe" sys "golang.org/x/sys/unix" ) +// OpenDevice offers a simpler file-open operation than the Go API's os.OpenFile (the Go API's +// operation causes some drivers to return busy). It also applies file validation prior to opening the device. func OpenDevice(path string, flags int, mode uint32) (uintptr, error) { fstat, err := os.Stat(path) if err != nil { @@ -23,13 +24,13 @@ func OpenDevice(path string, flags int, mode uint32) (uintptr, error) { return openDev(path, flags, mode) } -// open offers a simpler open operation than the Go API OpenFile. +// openDev offers a simpler file open operation than the Go API OpenFile. // See https://cs.opensource.google/go/go/+/refs/tags/go1.19.1:src/os/file_unix.go;l=205 func openDev(path string, flags int, mode uint32) (uintptr, error) { - var fd uintptr + var fd int var err error for { - fd, err = openat(sys.AT_FDCWD, path, flags, mode) + fd, err = sys.Openat(sys.AT_FDCWD, path, flags, mode) if err == nil { break } @@ -40,29 +41,10 @@ func openDev(path string, flags int, mode uint32) (uintptr, error) { return 0, &os.PathError{Op: "open", Path: path, Err: err} } - return fd, nil -} - -func openat(dirfd int, path string, flags int, mode uint32) (uintptr, error) { - pathPtr, err := sys.BytePtrFromString(path) - if err != nil { - return 0, err - } - - r1, _, errno := sys.Syscall6(sys.SYS_OPENAT, uintptr(dirfd), uintptr(unsafe.Pointer(pathPtr)), uintptr(flags), uintptr(mode), 0, 0) - if errno == 0 { - return r1, nil - } - - parsedErr := parseErrorType(errno) - switch parsedErr { - case ErrorUnsupported, ErrorSystem, ErrorBadArgument: - return 0, parsedErr - default: - return 0, errno - } + return uintptr(fd), nil } +// CloseDevice closes the device. func CloseDevice(fd uintptr) error { return closeDev(fd) }