void acc_set_device_num(int n, acc_device_t devtype ) ;

This function sets the device number and type for the accelerator device. The first argument "n" is the device number, which is usually an integer value. The second argument "devtype" specifies the type of the device, which can be a GPU, CPU, or another type of accelerator device.

Once the device number and type are set, subsequent computations can be executed on the specified device. This function is typically used in conjunction with other accelerator functions to specify the device on which the computations should be performed.

Note that the specific implementation of this function may vary depending on the programming language and accelerator framework being used.

相关问题

g_uevent_device_new 代码举例

以下是一个简单的 g_uevent_device_new 函数实现的示例代码：

#include <glib.h>
#include <gio/gio.h>

#define UEVENT_BUFFER_SIZE 2048

typedef struct _GUeventDevice GUeventDevice;

struct _GUeventDevice {
    GObject parent_instance;

    gchar *syspath;
    gchar *subsystem;
    gchar *devtype;
    gchar **filters;
    GRegex **regex_filters;
    guint n_filters;

    GIOChannel *io_channel;
    guint io_watch_id;
    gchar io_buffer[UEVENT_BUFFER_SIZE];
};

G_DEFINE_TYPE(GUeventDevice, g_uevent_device, G_TYPE_OBJECT);

static gboolean
g_uevent_device_io_watch_callback(GIOChannel *channel, GIOCondition condition,
                                  gpointer user_data)
{
    GUeventDevice *self = G_UEVENT_DEVICE(user_data);

    if (condition & G_IO_IN) {
        gsize bytes_read = 0;
        gsize io_buffer_size = sizeof(self->io_buffer) - 1;

        if (g_io_channel_read_chars(channel, self->io_buffer, io_buffer_size,
                                     &bytes_read, NULL) != G_IO_ERROR_NONE) {
            g_warning("Failed to read from uevent device");
            return G_SOURCE_REMOVE;
        }

        /* Null-terminate the read buffer */
        self->io_buffer[bytes_read] = '\0';

        /* Process the uevent messages in the buffer */
        gchar *line_start = self->io_buffer;
        gchar *line_end = NULL;

        while ((line_end = strchr(line_start, '\n'))) {
            *line_end = '\0';
            gchar **kv_pairs = g_strsplit(line_start, "=", -1);

            /* Process the key-value pairs in the uevent message */
            for (guint i = 0; kv_pairs[i]; i += 2) {
                gchar *key = kv_pairs[i];
                gchar *value = kv_pairs[i + 1];

                /* Filter out the key-value pairs that don't match any of the
                   regex filters */
                gboolean filter_match = FALSE;

                for (guint j = 0; j < self->n_filters; j++) {
                    if (g_regex_match(self->regex_filters[j], key, 0, NULL)) {
                        filter_match = TRUE;
                        break;
                    }
                }

                if (!filter_match) {
                    continue;
                }

                g_message("Received uevent message: %s=%s", key, value);
            }

            g_strfreev(kv_pairs);
            line_start = line_end + 1;
        }
    }

    return G_SOURCE_CONTINUE;
}

static void
g_uevent_device_init(GUeventDevice *self)
{
    self->syspath = NULL;
    self->subsystem = NULL;
    self->devtype = NULL;
    self->filters = NULL;
    self->regex_filters = NULL;
    self->n_filters = 0;
    self->io_channel = NULL;
    self->io_watch_id = 0;
}

static void
g_uevent_device_class_init(GUeventDeviceClass *klass)
{
    GObjectClass *object_class = G_OBJECT_CLASS(klass);

    object_class->finalize = (GObjectFinalizeFunc) g_free;
}

GUeventDevice *
g_uevent_device_new(const gchar *syspath, const gchar *subsystem,
                    const gchar *devtype, gchar **filters)
{
    GUeventDevice *self = g_object_new(G_TYPE_UEVENT_DEVICE, NULL);

    self->syspath = g_strdup(syspath);
    self->subsystem = g_strdup(subsystem);
    self->devtype = g_strdup(devtype);
    self->filters = g_strdupv(filters);

    /* Compile the regex filters */
    for (guint i = 0; self->filters[i]; i++) {
        GRegex *regex_filter = g_regex_new(self->filters[i], 0, 0, NULL);

        if (!regex_filter) {
            g_warning("Failed to compile regex filter: %s", self->filters[i]);
            continue;
        }

        self->regex_filters = g_realloc(self->regex_filters,
                                        (self->n_filters + 1) * sizeof(GRegex *));
        self->regex_filters[self->n_filters++] = regex_filter;
    }

    /* Open the uevent device file */
    gchar *uevent_path = g_build_filename(self->syspath, "uevent", NULL);
    GError *error = NULL;

    self->io_channel = g_io_channel_new_file(uevent_path, "r", &error);

    if (!self->io_channel) {
        g_warning("Failed to open uevent device: %s", error->message);
        g_error_free(error);
        g_object_unref(self);
        return NULL;
    }

    /* Add a watch for the IO channel */
    self->io_watch_id = g_io_add_watch(self->io_channel, G_IO_IN,
                                       g_uevent_device_io_watch_callback, self);

    g_free(uevent_path);

    return self;
}

这个示例代码演示了如何使用 GLib 和 GIO 库来创建一个 GUeventDevice 对象，该对象可以通过监听 Linux 内核的 uevent 消息来获取设备事件。GUeventDevice 对象可以指定一些过滤器，以只接收特定的 uevent 消息。在对象的销毁期间，将释放所有内存和资源。

udev_device_get_parent_with_subsystem_devtype使用的c/c++代码例子

下面是一个使用 `udev_device_get_parent_with_subsystem_devtype` 函数的 C++ 代码示例，它可用于查找与指定子系统和设备类型匹配的父设备：

#include <libudev.h>
#include <iostream>

int main() {
    struct udev* udev = udev_new();
    if (!udev) {
        std::cerr << "Failed to create udev context\n";
        return 1;
    }

    // Find the device by its subsystem and device type
    struct udev_enumerate* enumerate = udev_enumerate_new(udev);
    udev_enumerate_add_match_subsystem(enumerate, "tty");
    udev_enumerate_add_match_sysname(enumerate, "ttyS0");
    udev_enumerate_scan_devices(enumerate);

    struct udev_list_entry* devices = udev_enumerate_get_list_entry(enumerate);
    struct udev_list_entry* entry;
    struct udev_device* parent = NULL;

    udev_list_entry_foreach(entry, devices) {
        const char* path = udev_list_entry_get_name(entry);
        struct udev_device* device = udev_device_new_from_syspath(udev, path);

        // Get the parent device with matching subsystem and device type
        parent = udev_device_get_parent_with_subsystem_devtype(device, "pci", "pci_serial");

        udev_device_unref(device);

        if (parent) {
            break;
        }
    }

    if (parent) {
        const char* id = udev_device_get_property_value(parent, "ID_MODEL_FROM_DATABASE");
        if (id) {
            std::cout << "Parent device model: " << id << "\n";
        }
        else {
            std::cout << "Parent device model not found\n";
        }

        udev_device_unref(parent);
    }
    else {
        std::cout << "Parent device not found\n";
    }

    udev_enumerate_unref(enumerate);
    udev_unref(udev);

    return 0;
}

该示例首先创建了一个 `udev` 上下文，然后使用 `udev_enumerate_add_match_subsystem` 和 `udev_enumerate_add_match_sysname` 函数来指定要查找的设备的子系统和设备类型。然后，使用 `udev_enumerate_scan_devices` 函数扫描设备并获取设备列表。

接下来，该示例使用 `udev_list_entry_foreach` 宏来遍历设备列表，并使用 `udev_device_get_parent_with_subsystem_devtype` 函数查找具有匹配子系统和设备类型的父设备。如果找到了，则使用 `udev_device_get_property_value` 函数获取 `ID_MODEL_FROM_DATABASE` 属性的值，并将其打印到控制台上。

最后，该示例释放了所有 `udev` 对象。注意，该示例没有包含错误处理代码。