灯角

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灯角 2024-11-24 01:52:35

我似乎记得有一次当我忘记将函数声明为采用 void 时收到此(相当误导性)错误消息,这在 c(但不是 c++)中对于没有参数的函数是必需的:

struct f_lock *new_node()
{
   struct f_lock *new_f_lock;
   .....
   return new_f_lock;
}

应该是:

struct f_lock *new_node(void)
{
   struct f_lock *new_f_lock;
   .....
   return new_f_lock;
}

I seem to remember getting this (rather misleading) error message once when I had forgotten to declare a function as taking void which is required in c (but not c++) for functions with no parameters:

struct f_lock *new_node()
{
   struct f_lock *new_f_lock;
   .....
   return new_f_lock;
}

Should be:

struct f_lock *new_node(void)
{
   struct f_lock *new_f_lock;
   .....
   return new_f_lock;
}

警告:赋值使指针来自整数而不进行强制转换

灯角 2024-11-23 22:28:56

您使用 alert(jsonObj[0].key1)

You use alert(jsonObj[0].key1)

Javascript:如何访问对象内的匿名对象?

灯角 2024-11-23 20:02:27

我认为你想要的是不可能的,因为没有“仅插入”权限,如果你是表的编辑者,你实际上可以编辑和插入数据。

也许您可以在以下情况下执行类似的操作使用视图,因此用户可以更新此视图,但不能更新所有其他数据。也许您可以在用户插入数据后立即从可编辑视图中隐藏数据。当然,这必须被视为一种破解或解决方法。

I think what you want is not possible, as there is no "INSERT only" permission, if you are the editor of a table you actually can edit and insert data.

Maybe you can do something similar when using views, so a user can update this view, but not all the other data. Maybe you can hide the data from the editable view right after a user inserted it. Of course, this must be considered as a hack or workaround.

融合表权限:如何限制Android应用程序只能添加新条目?

灯角 2024-11-23 20:02:22

你可以找到解决这个问题的方法。但就我个人而言,我认为从外部容器捕获 IFrame 中的事件并不是一个好的做法。

you could find a way around this problem. But personally, I don't think its a good practice to capture events in an IFrame from an External Container.

如何检测带有外部内容的 iframe 上的 onmousedown?

灯角 2024-11-23 18:48:55

_mm_movepi64_pi64 从 XMM 移动到 MMX 寄存器。这不可能是正确的选择,除非您想在 MMX 寄存器中执行更多 SIMD,并且您的代码用完了 XMM 寄存器。

如果您希望这些位作为数组索引或其他内容,它们必须位于 GP 寄存器中,在这种情况下您需要 SSE4.1 _mm_extract_epi8

如果您需要坚持使用 SSE2,这应该是获取 xmm0 的字节 5 的最快方法:

pextrw eax, xmm0, 2
movzx eax, ah

因此,这应该有望使编译器变得像这样高效:

(uint8_t)(_mm_extract_epi16(var, n/2) >> ((n%2) * 8))

效率较低的是逐个移位 - bytes _mm_bsrli_si128 (psrldq) 将所需的字节放入 xmm reg 的低字节中,然后 movd (幸运的是,_mm_extract_epi16(var, 0) 发出 movd,而不是 pextrw r32, xmm, 0)。这样,如果您想要的字节是 pextw 将留在结果的高 8 中的奇数字节,则无需执行任何额外操作。仍然没有简单的方法可以将其与不是编译时常量的索引一起使用。

将 16B 存储到内存并加载您想要的元素应该相当不错。 (除非编译器将其优化为 pextract 指令,否则您可能会通过联合方法得到什么)。编译器将在堆栈上使用 16B 对齐的位置。因此,在这种情况下,存储->加载转发应该可以正常工作,因此延迟会很低。如果您需要将两个单独的元素放入两个单独的整数变量中,这可能是最好的选择,也许会击败多个 pextrw

_mm_movepi64_pi64 moves from XMM to MMX registers. There's no way it's the right choice, unless you want to do some more SIMD in MMX registers, and your code runs out of XMM regs.

If you want the bits as an array index or something, they have to be in a GP register, in which case you want SSE4.1 _mm_extract_epi8.

If you need to stick to SSE2, this should be the fastests way to get byte 5 of xmm0:

pextrw eax, xmm0, 2
movzx eax, ah

So this should hopefully get the compiler to be efficient like that:

(uint8_t)(_mm_extract_epi16(var, n/2) >> ((n%2) * 8))

Less efficient would be a shift-by-bytes _mm_bsrli_si128 (psrldq) to put the byte you want into the low byte of an xmm reg, then movd (_mm_extract_epi16(var, 0) emits movd, not pextrw r32, xmm, 0, fortunately). This way you don't have to do anything extra if the byte you want is an odd-numbered byte that pextw would leave in the high 8 of a result. Still no easy way to use this with an index that isn't a compile-time constant.

Storing 16B to memory and loading the element you want should be fairly good. (What you'll probably get with the union approach, unless the compiler optimizes it to a pextract instruction). The compiler will use a 16B-aligned location on the stack. Thus store->load forwarding should work fine in this case, so the latency will be low. If you need two separate elements into two separate integer variables, this is probably the best choice, maybe beating multiple pextrw

哪一个更快?

灯角 2024-11-23 18:25:01

您可以将子类声明为 Base 中的私有嵌套类

You can declare the child classes as private nested classes inside Base

C# 工厂方法和保护级别问题

灯角 2024-11-23 17:10:14

您可以从这里获取sdk。这是 android facebook 连接 的示例

You can get the sdk from here. This is a sample example of android faceebook connectivity

如何从 Android 应用程序连接或集成 facebook

灯角 2024-11-23 15:45:56

您在插入操作中分配内存,该内存是否已正确释放?

我应该建议使用 STL 容器,它可以最大限度地减少您必须编写的代码量:

#include <unordered_map>
#include <string>
#include <memory>

typedef std::unordered_map<std::string, std::shared_ptr<Powerdomain> > PowerdomainMap;

这应该具有您需要的所有功能以及内置内存安全性。

在 C++98 中,使用 std::tr1::unordered_map 等。

You are allocating memory in your insert operation, does that ever get deallocated properly?

I should recommend using STL containers which minimize the amount of code you have to write:

#include <unordered_map>
#include <string>
#include <memory>

typedef std::unordered_map<std::string, std::shared_ptr<Powerdomain> > PowerdomainMap;

This should have all the functionality you need with built-in memory safety.

In C++98, use <tr1/unordered_map> and std::tr1::unordered_map etc.

bison/flex 解析器的 Valgrind memcheck 结果分析

灯角 2024-11-23 14:45:18

除了密钥应该是唯一的之外,您无需声明密钥的任何必需属性,因此显而易见的解决方案是使用规范化的 IP 地址作为密钥。您可以通过显而易见的方式将地址转换为数字,但请注意 IPv6 地址会产生巨大的数字,因此无论您使用什么语言,都需要 BigInt 实现。

(如果您并不是实际上意味着所有 340 个 undecillion 地址都应该具有唯一的键,那么您当然应该查看普通的哈希函数。)

You don't state any required properties of the keys excet that thy should be unique, so the obvious solution is to use the canonicalized IP addresses as keys. You can turn the addresses into numbers the obvious way, but be warned that IPv6 addresses make for huge numbers, so you'll need the BigInt implementation in whatever language you use.

(If you didn't actually mean that all 340 undecillion addresses should have unique keys, then of course you should look at normal hash functions instead.)

独特的 KEY 生成算法

灯角 2024-11-23 13:16:38

如果您选择不使用 String.format,另一个选项是 + 二元运算符

String str = "Step " + a + " of " + b;

这相当于

new StringBuilder("Step ").append(String.valueOf(1)).append(" of ") .append(String.valueOf(2));

无论您使用哪个都是您的选择。 StringBuilder 更快,但速度差异很小。我更喜欢使用 + 运算符(它执行 StringBuilder.append(String.valueOf(X))) 并发现它更易于阅读。

If you choose not to use String.format, the other option is the + binary operator

String str = "Step " + a + " of " + b;

This is the equivalent of

new StringBuilder("Step ").append(String.valueOf(1)).append(" of ").append(String.valueOf(2));

Whichever you use is your choice. StringBuilder is faster, but the speed difference is marginal. I prefer to use the + operator (which does a StringBuilder.append(String.valueOf(X))) and find it easier to read.

如何在 Java 中格式化字符串

灯角 2024-11-23 11:30:24

嗯,根据我在 中找到的内容jQuery 的源代码,引擎本身不会创建未“正确定位”的标签(或片段)。即使传递一个字符串,jQuery 也会识别出已经提供了 header,并且不会生成它。

毕竟,当 jQuery 传递一个 HTML 字符串时,它实际上是在调用 document.createElement< /code> 并创建这些元素的数组列表。

编辑:经过更多调查后,看起来实际上是浏览器限制了元素创建,而不是 jQuery。不管怎样,你都会留下缺失的标签。这让我得出下面同样的结论。

尽管我不喜欢它,但可能是时候进行正则表达式/字符串操作了。

Well, based on what I can find in the source code of jQuery, the engine itself will not create tags (or fragments) that are not "properly seated". Even when passing a string, jQuery recognizes that the header has already been supplied and will not generate it.

After all, when jQuery is passed a string of HTML, it's actually calling document.createElement and creating an array list of those elements.

EDIT: After a little more investigation, it looks like it's the browser actually limiting element creation, not jQuery. Either way, you're left with absent tags. Which brings me to my same conclusion below.

As much as I don't like it, may be time for regex/string manipulation.

的 Jquery 选择器中的元素

灯角 2024-11-23 05:56:08

您还可以子类 UINavigationcontroller 并覆盖一些方法,如下所示:

- (id)initWithRootViewController:(UIViewController *)rootViewController {
    self = [super initWithRootViewController:rootViewController];
    if (self) {
        [self setCloseButtonToController:rootViewController];
    }
    return self;
}

- (void)dismissController {
    [self dismissViewControllerAnimated:YES completion:nil];
}

- (void)setCloseButtonToController:(UIViewController *)viewController {
    UIBarButtonItem *closeItem = [[UIBarButtonItem alloc] initWithTitle:@"Close" style:UIBarButtonItemStylePlain target:self action:@selector(dismissController)];
    [viewController.navigationItem setRightBarButtonItem:closeItem];
}

- (void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated {
    [super pushViewController:viewController animated:animated];

    [self setCloseButtonToController:viewController];

}

You can also subclass UINavigationcontroller and overide few methods like this:

- (id)initWithRootViewController:(UIViewController *)rootViewController {
    self = [super initWithRootViewController:rootViewController];
    if (self) {
        [self setCloseButtonToController:rootViewController];
    }
    return self;
}

- (void)dismissController {
    [self dismissViewControllerAnimated:YES completion:nil];
}

- (void)setCloseButtonToController:(UIViewController *)viewController {
    UIBarButtonItem *closeItem = [[UIBarButtonItem alloc] initWithTitle:@"Close" style:UIBarButtonItemStylePlain target:self action:@selector(dismissController)];
    [viewController.navigationItem setRightBarButtonItem:closeItem];
}

- (void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated {
    [super pushViewController:viewController animated:animated];

    [self setCloseButtonToController:viewController];

}

将相同的按钮添加到 UINavigationController 中的所有视图控制器

灯角 2024-11-23 02:59:59

您可能需要使用 Ant,但这应该可以满足您的要求:
http://jasperreports.sourceforge.net/sample.reference/antcompile/

You might need to use Ant, but this should do what you want:
http://jasperreports.sourceforge.net/sample.reference/antcompile/

是否有 .jrxml 文件的命令行编译器?

灯角 2024-11-22 21:34:34

基本上,您可以创建一个以 CURRENT_TIMESTAMP 作为默认值的 TIMESTAMP 列。
当您向该表插入行时,将自动插入当前日期/时间。
这就是您要找的吗?

顺便说一句:我建议从源头解决问题,并确保重复的主键不会插入到数据表中。
为此,您可以使用SELECT LAST_INSERT_ID();

basicly, you can create a TIMESTAMP column with CURRENT_TIMESTAMP as default value.
when you insert a row to that table, the current date/time will be automaticly inserted.
is that what you were looking for ?

BTW: i would recommend to kill the problem at it source and make sure a duplicate primary key will not be inserted to the datatable..
to do that, you can use the SELECT LAST_INSERT_ID();

将一个表中的所有行插入到另一个表中 +末尾的时间戳

灯角 2024-11-22 20:44:57

2022 年,只需将视频(例如 Mac 上的屏幕录制)拖放到 iPhone 模拟器中,它就会出现在“照片”中

In 2022, just drag and drop a video (screen recording on your mac for example) to the iphone simulator and it will be there in the Photos

如何将视频添加到 iPhone 模拟器

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