09-07-2003
Huh? Why did this get moved here? It happens on Linux (and probably others) as well.
Anyhoo, I figured it out, apparently pipes are page buffered unless the program itself is line buffered, on linux at least. Some versions of grep and sed have linebuffering options, but the ones on the solaris machine didn't, but you can get the effect by calling select()->flush() after printing a line in perl, so I just did my grepping in that.
10 More Discussions You Might Find Interesting
1. Windows & DOS: Issues & Discussions
Hello!
Will someone out there pls help in clearifying what is really wrong with my system. I use window 98 as my operating system. I am connected to a proxy server for browsing the net. Whenever l am listening to music online l have the problem of intermitted break in which the playing will... (10 Replies)
Discussion started by: kayode
10 Replies
2. Filesystems, Disks and Memory
Hello!
How I can increase or decrease predefined pipe buffer size?
System FreeBSD 4.9 and RedHat Linux 9.0
Thanks! (1 Reply)
Discussion started by: Jus
1 Replies
3. UNIX for Advanced & Expert Users
I am trying to figure out why when i have the following code
int main( { printf("0\n"); fork(); printf("1\n"); exit(0);}
and type in the shell
a.out | cat
the output of this program is
0
1
0
1
instead of
0
1
1
does anyone know? (3 Replies)
Discussion started by: Phantom12345
3 Replies
4. Shell Programming and Scripting
Hi,
I'm have a tcl application using expect. The application is connecting to a unix box and is running a script. What i need my app to do is show the output of the console as the script runs in realtime. At the moment, it my app is waiting until the script finishes and then dumps what is... (0 Replies)
Discussion started by: Phi01
0 Replies
5. Solaris
hi..
I have a question because there are files on Solaris and will not let me change the root user is the owner.
excuse is that I come from a Linux environment and I like to learn Solaris
thank (5 Replies)
Discussion started by: cejodrake
5 Replies
6. UNIX for Advanced & Expert Users
Hi,
There are three type of buffering: Fully buffered,line buffered,and unbuffered. The goal of the buffering provided by the standard I/O library is to use the minimum number of read and write calls.
I understand that decrease write() calls when use output function output data to a file ,... (4 Replies)
Discussion started by: Edward114
4 Replies
7. Programming
If a code forks 2 childs, what can the values be for the process id's of each of the child? I child pid is supposed to be 0, but what if you fork 2 of them? (5 Replies)
Discussion started by: omega666
5 Replies
8. Shell Programming and Scripting
Hello,
There's a third-party application's command that shows the application's status like "tail -f verybusy.log". When use the command, the output comes every 1-sec. but when it goes in a script below the output comes every 8-sec...What is the problem and how can I fix it?
open(CMD,... (2 Replies)
Discussion started by: Shawn, Lee
2 Replies
9. Solaris
Hello all.
I am new hear and would like to ask a question regarding to the Solaris Crash Analysis Tool.
We are analyzing the results of "thread summary" but not quite sure what the asterisk represents.
Following are the items that asterisk were attached.
50* threads sleeping on a semaphore (49... (1 Reply)
Discussion started by: YuW
1 Replies
10. Shell Programming and Scripting
The old buffering problem again, in a very specific case. On FreeBSD this time, but it's the generic line-buffered vs fully-buffered problem.
I'm trying to pick an available bluetooth speaker (all named audio_N), by pinging all of them en mass and taking the first to respond.
The... (10 Replies)
Discussion started by: Juha Nurmela
10 Replies
LEARN ABOUT ULTRIX
setlinebuf
setbuf(3s) setbuf(3s)
Name
setbuf, setbuffer, setlinebuf, setvbuf - assign buffering to a stream
Syntax
#include <stdio.h>
void setbuf(stream, buf)
FILE *stream;
char *buf;
void setbuffer(stream, buf, size)
FILE *stream;
char *buf;
int size;
void setlinebuf(stream)
FILE *stream;
int setvbuf(stream, buf, type, size)
FILE *stream;
char *buf;
int type; size_t size;
Description
The three types of buffering available are unbuffered, block buffered, and line buffered. When an output stream is unbuffered, information
appears on the destination file or terminal as soon as written; when it is block buffered many characters are saved up and written as a
block; when it is line buffered characters are saved up until a new line is encountered or input is read from stdin. The routine may be
used to force the block out early. Normally all files are block buffered. For further information, see A buffer is obtained from upon the
first or on the file. If the standard stream stdout refers to a terminal it is line buffered. The standard stream stderr is always
unbuffered.
The routine is used after a stream has been opened but before it is read or written. The character array buf is used instead of an auto-
matically allocated buffer. If buf is the constant pointer NULL, input/output will be completely unbuffered. A manifest constant BUFSIZ
tells how big an array is needed:
char buf[BUFSIZ];
The routine, an alternate form of is used after a stream has been opened but before it is read or written. The character array buf whose
size is determined by the size argument is used instead of an automatically allocated buffer. If buf is the constant pointer NULL,
input/output will be completely unbuffered.
The routine is used to change stdout or stderr from block buffered or unbuffered to line buffered. Unlike and it can be used at any time
that the file descriptor is active.
The routine may be used after a stream has been opened but before it is read or written. Type determines how stream will be buffered.
Legal values for type, defined in stdio.h are:
_IOFBF causes input/output to be fully buffered.
_IOLBF causes output to be line buffered; the buffer will be flushed when a new line is written, the buffer is full, or input is
requested.
_IONBF causes input/output to be completely unbuffered.
If buf is not the NULL pointer, the array it points to will be used for buffering, instead of an automatically allocated buffer. The size
specifies the size of the buffer to be used. The constant BUFSIZ in <stdio.h> is suggested as a good buffer size. If input/output is
unbuffered, buf and size are ignored.
By default, output to a terminal is line buffered and all other input/output is fully buffered.
A file can be changed from unbuffered or line buffered to block buffered by using For further information, see A file can be changed from
block buffered or line buffered to unbuffered by using followed by with a buffer argument of NULL.
Restrictions
The standard error stream should be line buffered by default.
The and functions are not portable to non 4.2 BSD versions of UNIX.
See Also
malloc(3), fclose(3s), fopen(3s), fread(3s), getc(3s), printf(3s), putc(3s), puts(3s).
setbuf(3s)