UNIX for Advanced & Expert Users

Hi,

How do I know the max. size for FIFO(named pipe) on my system.
I'm using solaris 10 OS. Is there any comparison chart between message queues and named pipes.

Thanks in advance.

I guess it's 5K (I got this information from `ulimit -p` in a bash shell).

Find out what PIPE_BUF is set to in limits.h and read the manpage of the write system call.

Thanks shamrock & toshiro

It's defined 5K in limits.h
#define PIPE_BUF 5120 /* max # bytes atomic in write to a pipe */

Oh. I see what you asked. But that is not what PIPE_BUF is. Solaris does know the size of a pipe file - fstat() on the open file descriptor returns a struct stat with st_size in bytes. This is the amount of data waiting to be read from the pipe. Other versions of unix do not support this extension to stat functionality.

PIPE_MAX is 'how many bytes can I stuff into a pipe with a single call to write, and still have the call complete atomically'

It is not clear to me which one you want. But you have choices.