在C ++中寻找大于4GB的文件? [英] Seeking in a file that is more than 4GB in C++?

问题描述

我正在使用MS Visual Studio 2012编译器，并且正在以x64发布模式进行构建.

I am using the MS Visual Studio 2012 compiler and I am building in x64 release mode.

使用ifstream可以读取大于4GB的文件.问题是，我无法找到10GB文件中间的位置.

Using ifstream I can read files larger than 4GB. The problem is, I can't seek to a position in the middle of a 10GB file.

当我像这样的is.seekg (5368709120, is.beg);使用seekg时，is.tellg();返回-1，这意味着搜索失败.我确定文件存在并且位置5368709120也存在.如果我使用以下命令，它的工作效果就很好:例如is.seekg (100, is.beg);.

When I use seekg like this is.seekg (5368709120, is.beg); then is.tellg(); returns -1 which means the seek failed. I am sure that the file exists and the position 5368709120 exists too. It works perfectly fine if I use: is.seekg (100, is.beg); for example.

不能选择使用多次搜寻，因为文件可以达到300GB(并且使用多次搜寻会很慢).

Using multiple seeks is not an option since the files can get up to 300GB (and using many seeks will be slow).

我的问题是:如何在不使用多次搜索的情况下使搜索在10GB的文件上正常工作?

推荐答案

如何在不使用多次搜索的情况下使搜索在10GB的文件上正常工作?

how can I get seek to work correctly on a 10GB file without using multiple seeks?

将您的帖子剩下的一秒忘了，这个问题的答案(在Windows中)非常简单:使用

Forgetting for a second the rest of your post, the answer to this question (in Windows) is very simple: use _fseeki64. I don't see a problem with dropping down to a lower level API when dealing with huge files -- you'd most likely be doing large chunk read/writes anyway right? You can easily use fread and fwrite for that.

如果您坚持使用STL，Microsoft的实施将无法正常进行.我听说STLPort处理大文件查找，因此您可以这样做.不过，这是一种很费力的方法，我会坚持使用基本的fseek.

If you insist on STL, Microsoft's implementation won't work. I've heard STLPort handles large file seeking, so you could go for that. It's a rather heavy handed approach though, I'd stick with the basic fseek.

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