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.
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.)