Seeking in large files with ifstream

Question

I'm implementing a program in C++ using ifstream that must seek in large files (~1TB). However, this fails after reading 2GB. Is there a way to get file positions, even for large files? I compile for a 32-bit windows machine.

std::ifstream f;
f.open( filename.c_str(), std::ifstream::in | std::ifstream::binary );
while(true) {
    std::cout << (uint64_t)(f.tellg()) << std::endl;
    //read data
}

I don't know if this actually changes anything, but have you tried using the plain C alternative of reading files? — stefan, Jul 12 '12 at 09:44
@stefan has plain C file-position handler which size is greater than 32 bits? — triclosan, Jul 12 '12 at 11:01

score 2 · Accepted Answer · answered Jul 12 '12 at 09:51

2

Since you are compiling on a 32-bit platform, if you use fstream, you are going to get 32-bits access. To access large files, you need to use a platform dependent solution :

for windows, use _lseeki64()
for linux, use lseek64()

answered Jul 12 '12 at 09:51

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I will use these functions. Thank you! – Patrik Jul 14 '12 at 15:27

Seeking in large files with ifstream

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