Fastest way to write large STL vector to file using STL

Question

I have a large vector (10^9 elements) of chars, and I was wondering what is the fastest way to write such vector to a file. So far I\'ve been using next code:

ve         


        

Answer 1

Since your data is contiguous in memory (as Charles said), you can use low level I/O. On Unix or Linux, you can do your write to a file descriptor. On Windows XP, use file handles. (It's a little trickier on XP, but well documented in MSDN.)

XP is a little funny about buffering. If you write a 1GB block to a handle, it will be slower than if you break the write up into smaller transfer sizes (in a loop). I've found the 256KB writes are most efficient. Once you've written the loop, you can play around with this and see what's the fastest transfer size.