iostream和大文件支持 [英] iostream and large file support

问题描述

我正在开发一个使用GCC的C ++应用程式Linux上的4.x（32位操作系统）。这个应用程序需要能够读取大小> 2GB的文件。

我真的想使用iostream东西与FILE指针，但我找不到大文件#defines（_LARGEFILE_SOURCE，_LARGEFILE64_SOURCE，_FILE_OFFSET_BITS = 64）对iostream头有任何影响。

我在32位系统上编译。任何指针都会有所帮助。

谢谢！

解决方案

已经在你编译 libstdc ++ 时决定，通常取决于 _GLIBCXX_USE_LFS 是否在<$ c如果有疑问，请传递您的可执行文件（或 libstdc ++。）。

，如果通过 readelf -r （或通过 strings ）动态链接）查看你的二进制文件/ libstdc ++ 是否链接到 fopen / fseek /等等。或 fopen64 / fseek64 / etc。

UPDATE

您不必担心2GB限制，只要您不需要/尝试 fseek 或 ftell （您只是读取或写入串流）。

I'm trying to find a definitive answer and can't, so I'm hoping someone might know.

I'm developing a C++ app using GCC 4.x on Linux (32-bit OS). This app needs to be able to read files > 2GB in size.

I would really like to use iostream stuff vs. FILE pointers, but I can't find if the large file #defines (_LARGEFILE_SOURCE, _LARGEFILE64_SOURCE, _FILE_OFFSET_BITS=64) have any effect on the iostream headers.

I'm compiling on a 32-bit system. Any pointers would be helpful.

Thanks!

解决方案

This has already been decided for you when libstdc++ was compiled, and normally depends on whether or not _GLIBCXX_USE_LFS was defined in c++config.h.

If in doubt, pass your executable (or libstdc++.so, if linking against it dynamically) through readelf -r (or through strings) and see if your binary/libstdc++ linked against fopen/fseek/etc. or fopen64/fseek64/etc.

UPDATE

You don't have to worry about the 2GB limit as long as you don't need/attempt to fseek or ftell (you just read from or write to the stream.)

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