几年没有写C了，在C中如何提高IO中写的速度,一般有什么技巧？

loufangxin

我面程序中会用到fprintf和fwrite交叉调用，经调试，发现写得很慢，一般只能写入4M/s(笔忘本上),不知有没有办法提高？

ilike911

#include <stdio.h>;
  int setvbuf( FILE *stream, char *buffer, int mode, size_t size );



The function setvbuf() sets the buffer for stream to be buffer, with a size of size. mode can be:

_IOFBF, which indicates full buffering
_IOLBF, which means line buffering
_IONBF, which means no buffering

if you use linux, should also to check hd wich hdparm to confirm it's in 32bit i/o.

loufangxin

Thank ilike911.

loufangxin

After I setvbuf to a 256k buf, the IO write performance got 50% improvement, when I try to setvbuf on IO read, it did not help.