storage

在使用solidity开发以太坊智能合约时，可以为变量声明memory和storage关键字。那么，它们有什么不同之处？如果在声明合约变量时没有使用memory关键字，Solidity会尝试在storage中存储这个变量。 storage是什么 根据Solidity首席工程师Chriseth的说法： “你可以把storage想像成一个大数组，它有自己的结构，这个结构是由你的合约中的状态变量所决定的，因此在运行时不能改变” 。 这就是说，storage的结构是在合约部署创建时，根据你的合约中状态变量的声明，就固定下来了，并且不能在将来的合约方法调用中改变这个结构。但是，storage中的内容是可以通过交易来改变的。这些交易调用因此将修改合约的状态，这也是为什么合约中的变量被称为状态变量的原因。因此在合约层面声明的一个uint8类型的storage变量， 它的值可以修改为任何0-255之间的有效uint8值，但是该变量在storage结构中的位置始终不会变化。 函数中的变量 如果你在合约函数中声明变量时没有使用memory关键字，那么solidity将会尝试使用storage结构，目前来讲，这样做可以通过编译，但是可能导致不可预期的结果。memory关键字告诉solidity应当在该函数运行时为变量创建一块空间，使其大小和结构满足函数运行的需要。

I'm using docker nextcloud. I created a clean instance and I want to use the application external storage. I managed to configure successfully a local storage using the following command : mount_id=$(docker exec --user 1000 nextcloud php occ files_external:create Home local null::null -c datadir=/var/www/data --output=json) docker exec --user 1000 nextcloud php occ files_external:applicable --add-user=foo "$mount_id" I can create/move/copy folder and files but when I want to delete a created folder I got the following error : Error deleting file "folderfoo". It's says it's a file but actually

I have a situation where a user is attaching files within an application, these files are then persisted to Azure Blob storage, there is a reasonable likelihood that there are going to be duplicates and I want to put in place a solution where duplicate blobs are avoided. My first thought is to just name the blob as filename_hash but that only captures a subset of duplicates, then filesize_hash was then next thought. In doing this though it seems like I am losing some of the flexibility of the blob storage to represent the position in a hierarchy of the file, see: Windows Azure: How to create

I am working on an application where I have created some directory which I am accessing through my application I want to make that directory hidden for security purpose .Such that the user can access them only within the application does not access them outside the application as like through file manager. Any help is appreciated. Don't make it duplicate because I search out all the answer, but no one has worked for me. schrej Just appending a dot before the folder name will not protect it . It is only invisible to the user. It can still be accessed from apps, including file managers and

For example: #include <thread> thread_local int n = 1; void f() { ++n; // is n initialized here for each thread or prior to entering f()? } int main() { std::thread ta(f); std::thread tb(f); ta.join(); tb.join(); } It's still not entirely clear from here when is n initialized. Simple enough, and all according to specification. n is going to be initialized whenever the new thread is run - before you enter any thread-specific functions. To be exact, it is going to be initialized three times. 来源： https://stackoverflow.com/questions/35508133/when-exactly-is-a-thread-local-variable-declared-at

When I install my app on my main/new phone, the installed size is around 18.5MB and when I install my app on an old Samsung Galaxy Ace (Mk1), for some reason, it installs with pretty much the same size, as you see here: It runs perfectly on my main phone, but obviously, the old Galaxy Ace really struggles with it. Now, I download a random game from the Play Store and with that one you can see the results here: Much better, it takes up less space on the less capable phone than it does on the more capable phone. However, my question is, where can I start to try to figure out why my app doesn't