10-16-2008
Quote:
Originally Posted by
shamrock
You're not capturing the return value of the dupPipe function in main() outlined in red. The newly created destfd is lost so you can't connect the two processes together.
I think I have figured it out. I am creating a new pipe for every process in the for -loop( not shown in the code).
I am not anymore.
Now I am able to do for example ls|wc. but I have to finish whit an Enter. I think it has to do whit not closed pipe ends in parent.
10 More Discussions You Might Find Interesting
1. Programming
I have encountered a strange problem dealing with pipes
and forking. The program basicaly does this:
cat file | tbl | eqn | groff
Now, I have a parent process that forks children
that that exec the stuff that they should. The pipes defined
in the parent are the ones used.
The chain goes... (1 Reply)
Discussion started by: denoir
1 Replies
2. Shell Programming and Scripting
I use read often in scripts to filter the right part into a variable like:
$ print "abc cde efg" | read k l ; print "k=$k, l=$l"
k=, l=
This works on linux and unix versions I work with. On OSX 10.4 this
doesn't work. I found a workaround but would like to know
why the original line... (5 Replies)
Discussion started by: relyveld
5 Replies
3. Shell Programming and Scripting
Basically I am trying to write a short script to report total space used on /u0? file systems. This is what I was trying to do:df -k /u0? | grep -v kbytes | awk '{ printf $2 "+" }' | sed s/.$// | bcBut it returns no output.
This works however: > A=`df -k /u0? |grep -v kbytes | awk '{ printf $2... (2 Replies)
Discussion started by: 98_1LE
2 Replies
4. Programming
Is there a way to know whether is pipe is opened in read or write mode.I mean is there any signal that is generated when a pipe is opened in read or write mode.
If you have some solution .please let me know ........ (2 Replies)
Discussion started by: vivivo2000
2 Replies
5. UNIX for Dummies Questions & Answers
Hello everyone
I got a school project that was due yesterday so i really would aprreciate some help
the following is an example of the input file (bateriaTestes)
1 caeiro 2000 d
2 pessoa 100 w
3 campos 200 b
4 soares 500 w
simple 4 field lines. lines separated by \n and fields by... (1 Reply)
Discussion started by: zemanel
1 Replies
6. Programming
Hi,
Can any one please help me with this. Am struggling hard to get a solution.
I am doing telnet through a C program and getting the stdout file descriptor of the remote machine to pipe.
read() function is getting data, But whenl it receives SOH character ie. ^A ( Start of heading = Console... (2 Replies)
Discussion started by: JDS
2 Replies
7. Shell Programming and Scripting
Hello !
I want to process a text file in order to extract desired data using sed and grep... Now I am facing a problem piping to grep... nothing happens..
The text consists of blocks of 3 lines that may (or not) contain the Desired data.
the desired data is on each 2... (4 Replies)
Discussion started by: ShellBeginner
4 Replies
8. UNIX for Dummies Questions & Answers
hi i am having issues with extra pipe.
i have a data file and i need to remove the extra pipe in the(example 4th and 7thline) in datafile. there are many other line and filed like this which i need to remove from files. The sample data is below:
270 31|455004|24/03/2010|0001235|72
271... (3 Replies)
Discussion started by: abhi_n123
3 Replies
9. Programming
Hi all,
Im trying to do a simple program which ask the user for a unix command with the arguments. The program fork and the two process communicate with pipes. The child process call execvp with the command and the father process read the result of the execvp via the pipe.
This program works... (11 Replies)
Discussion started by: blackmamba21
11 Replies
10. Shell Programming and Scripting
Hi,guys:
I want to use c to implement a pipe. For example:
ps auxwww | grep fred | more
I forked three child processes. Each is responsible for each command, and pipe to next one.
for(i=0;i<2;i++)
pipe(fd)
if(child==1) // child 1
{
close(1)
dup2(fd,1)
close(fd)
}... (3 Replies)
Discussion started by: tomlee
3 Replies
EXECUTE(7) SQL Commands EXECUTE(7)
NAME
EXECUTE - execute a prepared statement
SYNOPSIS
EXECUTE name [ ( parameter [, ...] ) ]
DESCRIPTION
EXECUTE is used to execute a previously prepared statement. Since prepared statements only exist for the duration of a session, the pre-
pared statement must have been created by a PREPARE statement executed earlier in the current session.
If the PREPARE statement that created the statement specified some parameters, a compatible set of parameters must be passed to the EXECUTE
statement, or else an error is raised. Note that (unlike functions) prepared statements are not overloaded based on the type or number of
their parameters; the name of a prepared statement must be unique within a database session.
For more information on the creation and usage of prepared statements, see PREPARE [prepare(7)].
PARAMETERS
name The name of the prepared statement to execute.
parameter
The actual value of a parameter to the prepared statement. This must be an expression yielding a value that is compatible with the
data type of this parameter, as was determined when the prepared statement was created.
OUTPUTS
The command tag returned by EXECUTE is that of the prepared statement, and not EXECUTE.
EXAMPLES
Examples are given in the Examples [prepare(7)] section of the PREPARE [prepare(7)] documentation.
COMPATIBILITY
The SQL standard includes an EXECUTE statement, but it is only for use in embedded SQL. This version of the EXECUTE statement also uses a
somewhat different syntax.
SEE ALSO
DEALLOCATE [deallocate(7)], PREPARE [prepare(7)]
SQL - Language Statements 2010-05-14 EXECUTE(7)