[Ygg2]

Not if you are doing buffered reads, where you replace slow file access with fast memory access. This buffer is cleared every X bytes processed.

Writing to it would be pointless because clears obliterate anything written; or inefficient because you are somehow offsetting clears, which would sabotage the buffered reading performance gains.

[lelanthran]

Maybe I missed it, but ITT we were talking about C buffers, not buffered reads.

[Ygg2]

I thought we were talking about high performance parsing. Of which buffered reads are one. Other is loading entire document into mutable memory, which also has limitations.