Sponsored Content
Full Discussion: pipe help
Top Forums Programming pipe help Post 16175 by Perderabo on Tuesday 26th of February 2002 03:07:04 PM
Old 02-26-2002
Nothing that you're saying makes any sense at all.

A process has total control over when a child is created. When it invokes fork(), that is exactly when the process is created. The child exists when the very next statement is executed.

There is no need at all to synchonize the reading and writing on a pipe. The reader do can invoke read() hours before the data is written...it will simply wait unless it sets O_NDELAY in which case it returns immediately...so don't set that option. The reader can also read() hours after the write() on the other end. The data will wait. Neither case can cause a broken pipe, which is the error you complained about. That is caused by the reader exiting prior to the write.

Your real problem is that you'e trying to run a marathon when you can't yet walk.

If you attempt to use pipes in a full-duplex manner or use two pipe to achieve a two-way communication between processes, you will almost certainly cause deadlock. Get the data flowing in a single direction before you try to move on.
 

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

pipe | question

how do you pipe the results to next statement as argument? somecommand | grep $result somefile how do you reference $result with?? (12 Replies)
Discussion started by: convenientstore
12 Replies

2. UNIX for Advanced & Expert Users

Broken Pipe

Hi I tried to open the man page of sh and piped to `pg`. Normally while reading a file page by page using `pg`, if we wanna quit at the middle of file, we give "q" near the colon mode. Ex1: $cat file1 | pg hi how r u : (page1) now press "return key", it will go to next page yes i ... (1 Reply)
Discussion started by: ramkrix
1 Replies

3. UNIX for Dummies Questions & Answers

Broken Pipe

Hi I tried to open the man page of sh and piped to `pg`. Normally while reading a file page by page using `pg`, if we wanna quit at the middle of file, we give "q" near the colon mode. Ex1: $cat file1 | pg hi how r u : (page1) now press "return key", it will go to next page yes i ... (3 Replies)
Discussion started by: ramkrix
3 Replies

4. Programming

Pipe error

hi guys, o have a big error in this program but i cant solve someone ?! #include <stdlib.h> #include <stdio.h> #include <unistd.h> #include <string.h> int main(int argc, char *argv){ int cont = 2, posicao; char geraArquivo= "|cat>>", espaco=" "; char nomeArquivo, comando,... (11 Replies)
Discussion started by: beandj
11 Replies

5. Shell Programming and Scripting

How can I use pipe

Hi, guys: I am working on my shell using c. How can I use pipe to implement the following? ls -l 1>> | grep hellp 1<< 2>> | less 2<< (the output of ls goes to grep, and the output of grep goes to less) Thanks Please use and tags when posting code, data or logs etc. to preserve... (1 Reply)
Discussion started by: tomlee
1 Replies

6. Shell Programming and Scripting

Replace pipe with Broken Pipe

Hi All , Is there any way to replace the pipe ( | ) with the broken pipe (0xA6) in unix (1 Reply)
Discussion started by: saj
1 Replies

7. Shell Programming and Scripting

How do I use pipe in perl

I want to do the following in perl: print $output | grep ' something' | awk '{print $2}'; I know there is system(); but it does not behave the way I was expecting it in perl. (2 Replies)
Discussion started by: streetfighter2
2 Replies

8. Programming

pipe() - Sincronization

Hi guys. I've a problem with pipes, I'm trying to make a program that can create a child process and they must generate the folowing output: Ping ... Pong Ping ... Pong Ping ... Pong I want syncronize the output whithout using the semephores, can anyone help me? Thanks in advance. /** *... (1 Reply)
Discussion started by: pharaoh
1 Replies

9. Shell Programming and Scripting

How to use an input pipe ?

Hi all, I would like to use properly an input pipe, like this : cat myFile.txt | myCommand.shI always find this solution : while read line; do ...; donebut I have a great lost of performance ! On a big file, with a simple grep, I can spend 2400 times more time ! oO (from 0,023sec to 1m)... (4 Replies)
Discussion started by: LeNouveau
4 Replies

10. Shell Programming and Scripting

How to ignore Pipe in Pipe delimited file?

Hi guys, I need to know how i can ignore Pipe '|' if Pipe is coming as a column in Pipe delimited file for eg: file 1: xx|yy|"xyz|zzz"|zzz|12... using below awk command awk 'BEGIN {FS=OFS="|" } print $3 i would get xyz But i want as : xyz|zzz to consider as whole column... (13 Replies)
Discussion started by: rohit_shinez
13 Replies
vprintf(3int)															     vprintf(3int)

Name
       vprintf, vfprintf, vsprintf - print formatted output of a varargs argument list

Syntax
       #include <stdio.h>
       #include <varargs.h>

       int vprintf ( format, ap )
       char *format;
       va list ap;

       int vfprintf ( stream, format, ap )
       FILE *stream;
       char *format;
       va list ap;

       int vsprintf ( s, format, ap )
       char *s, *format;
       va list ap;

Description
       The international functions and are similar to the standard I/O functions.

       Likewise,  the  vprintf functions are similar to the printf functions except they are called with an argument list as defined by instead of
       with a variable number of arguments.

       The international functions allow you to use the %digit$ conversion character in place of the % character  you  use  in	the  standard  I/O
       functions.   The digit is a decimal digit n from 1 to 9.  The international functions apply conversions to the nth argument in the argument
       list, rather than to the next unused argument.

       You can use the % conversion character in the international functions.  However, you cannot mix the % conversion character with the %digit$
       conversion character in a single call.

       You  can  indicate  a  field  width or precision by an asterisk (*) instead of a digit string in format strings containing the % conversion
       character. If you use an asterisk, you can supply an integer arg that specifies the field width or precision.  In format strings containing
       the  %digit$  conversion character, you can indicate field width or precision by the sequence *digit$.  You use a decimal digit from 1 to 9
       to indicate which argument contains an integer that specifies the field width or precision.

       The conversion characters and their meanings are identical to

       You must use each digit argument at least once.

Examples
       #include <stdio.h>
       #include <varargs.h>

       main()
       {
       char *function_name = "vpr";
       char *arg1 = "hello world";
       int arg2 = 2;
       char *arg3 = "study";

       char *i18nfmt = "%1$s %3$d
";

       test(function_name, i18nfmt, arg1, arg2, arg3);
       }

       test(va_alist)
       va_dcl
       {
       va_list args;
       char *fmt;
       char string[1024];

       va_start(args);

       (void)printf("function %s: ", va_arg(args, char *));

       fmt = va_arg(args, char *);

       (void)vprintf(fmt, args);

       va_end(args);
       }

See Also
       setlocale(3), scanf(3int), printf(3s), printf(3int), vprintf(3s), putc(3s), scanf(3s), stdio(3s), varargs(3)
       Guide to Developing International Software

																     vprintf(3int)
All times are GMT -4. The time now is 05:36 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy