file streams

[Bill Cunningham]

Is there any benefit to using any of the buffering functions when
reading and writing to disk? For example setlinebuf(). I understand by
default file streams are read as blocks. Does line buffering add any
benefits for certain situations? And what are these "unlocking" versions of
stream functions in the stdio library?

Bill

 

[Siri Crews]

Is there any benefit to using any of the buffering functions when
reading and writing to disk? For example setlinebuf(). I understand by

Potentially there's a disk read for every block with a partial write, and a disk
write for each full or partial write. Ideally the kernel, if any, is bufferring
blocks and does the minimal disk activity. If the system has a privileged state
kernel, it needs a context switch everytime a write is called in the kernel.

default file streams are read as blocks. Does line buffering add any
benefits for certain situations? And what are these "unlocking" versions of

Unbufferred or line bufferred reduces the risk of losing partial output if the
program aborts. It can increase the time spent in context switches and disk I/O.