Sponsored Content
Full Discussion: question about popen in C
Top Forums Programming question about popen in C Post 302505006 by Corona688 on Wednesday 16th of March 2011 12:59:30 AM
Old 03-16-2011
Quote:
Originally Posted by omega666
what about

also when getting the exit code using pclose_new for the popen_new using "r" i get the return to be 141 but when used by "w" i get 0.....
why am i getting 141
I can't tell from here. Please post your current code and exactly what you did with it.
Quote:
also can a pointer to a file ever be the value 0
No. Then you wouldn't be able to tell it apart from NULL.
Quote:
and can a pid value ever be 0?
No.
 

10 More Discussions You Might Find Interesting

1. Programming

question about popen();

Hi The following is my program to test popen() routine. The purpose is to print some contents of the corrent directory. But in fact, the output is only one character 'a', which I believe is the first char of the file "a.out". So, can anybody tell me what is wrong about this program?... (2 Replies)
Discussion started by: dell9
2 Replies

2. Programming

query in popen

hai friends I have written a tcp chat server in c.. I have designed a cgi program in c to control it... When i try to start the server from the cgi program, it is not starting. Why is that ? I have even tried giving the root ownership for all the programs.. Still its not. I have used the... (1 Reply)
Discussion started by: collins
1 Replies

3. Programming

popen and tar, please HELP!

Hi there, I'm facing a problem running the tar command with the popen function. FILE* fp = popen("tar czf - textfile","r") // output this program should give the output to the stdout. I don't know if it is possible and which function like fprint() etc. should I use. I suppose that I... (4 Replies)
Discussion started by: stef83
4 Replies

4. Programming

using popen with background process

hi, how to work with a background process without a controlling terminal to make use of popen or system call ? when ever i use popen or system function call in foreground process, there is no problem with respect to that .. but when the same program is run as a background process without a... (7 Replies)
Discussion started by: matrixmadhan
7 Replies

5. Shell Programming and Scripting

Python: popen problems

Hello I'm writing a web server in python(obelisk-http.sourceforge.net) and I'm having a greeat problem with POST method it like that When someone make a POST request to the server it must open the executable(perl/python/.exe/elf) and send to the STANDART in (stdin) the request and get the... (2 Replies)
Discussion started by: sendai
2 Replies

6. Programming

prolems with pipes and popen in c

Hi! I'm trying to write a c program. The child process must transmit to the parent a file name and the parent must count the lines from the file and return te result to the child. Here is what i've done. It doesn't stop running, I guess. I'm sorry if it's an ugly code, i'm new at this stuff,... (2 Replies)
Discussion started by: alina89
2 Replies

7. UNIX for Advanced & Expert Users

popen and pclose solved

Hi I am trying to use popen function with wrtie option to give inputs to ftp command. #include "stdio.h" int main(int argv ,char *argc) { int size=0; char *buf; FILE *fp; fp = popen("ftp","w"); while(getline(&buf,&size,stdin) != -1) write(fp,buf);... (0 Replies)
Discussion started by: kumaran_5555
0 Replies

8. Programming

segmentation fault while using popen

hi, i am trying to use popen to run a grep process and check if the pattern exists in the file that i am searching in. i am getting segmentation fault when i try to execute the following code char *cd; char flag; char hdr_flpsp; char hdr_flpsp2; FILE *fp; printf ("program starts");... (1 Reply)
Discussion started by: sais
1 Replies

9. Programming

question about system and popen in C

in man system it talks about SIGCHLD will be blocked, and SIGINT and SIGQUIT will be ignored. Does this signal stuff also happen in popen command? (even though man popen says nothing about signals) also if I am not using wait(&status) and I am using waitpid(pid, NULL, 0) how would... (1 Reply)
Discussion started by: omega666
1 Replies

10. Programming

Popen problem

Hello all, I am reading a huge zip file in POPEN process and then writting that to a normal file which of 2GB. Now the process is failing when I looked for the cause someother process comming in after I read my file and it is deleting the zip. But in theory the popen command should read the... (5 Replies)
Discussion started by: arunkumar_mca
5 Replies
SHELL-QUOTE(1p) 					User Contributed Perl Documentation					   SHELL-QUOTE(1p)

NAME
shell-quote - quote arguments for safe use, unmodified in a shell command SYNOPSIS
shell-quote [switch]... arg... DESCRIPTION
shell-quote lets you pass arbitrary strings through the shell so that they won't be changed by the shell. This lets you process commands or files with embedded white space or shell globbing characters safely. Here are a few examples. EXAMPLES
ssh preserving args When running a remote command with ssh, ssh doesn't preserve the separate arguments it receives. It just joins them with spaces and passes them to "$SHELL -c". This doesn't work as intended: ssh host touch 'hi there' # fails It creates 2 files, hi and there. Instead, do this: cmd=`shell-quote touch 'hi there'` ssh host "$cmd" This gives you just 1 file, hi there. process find output It's not ordinarily possible to process an arbitrary list of files output by find with a shell script. Anything you put in $IFS to split up the output could legitimately be in a file's name. Here's how you can do it using shell-quote: eval set -- `find -type f -print0 | xargs -0 shell-quote --` debug shell scripts shell-quote is better than echo for debugging shell scripts. debug() { [ -z "$debug" ] || shell-quote "debug:" "$@" } With echo you can't tell the difference between "debug 'foo bar'" and "debug foo bar", but with shell-quote you can. save a command for later shell-quote can be used to build up a shell command to run later. Say you want the user to be able to give you switches for a command you're going to run. If you don't want the switches to be re-evaluated by the shell (which is usually a good idea, else there are things the user can't pass through), you can do something like this: user_switches= while [ $# != 0 ] do case x$1 in x--pass-through) [ $# -gt 1 ] || die "need an argument for $1" user_switches="$user_switches "`shell-quote -- "$2"` shift;; # process other switches esac shift done # later eval "shell-quote some-command $user_switches my args" OPTIONS
--debug Turn debugging on. --help Show the usage message and die. --version Show the version number and exit. AVAILABILITY
The code is licensed under the GNU GPL. Check http://www.argon.org/~roderick/ or CPAN for updated versions. AUTHOR
Roderick Schertler <roderick@argon.org> perl v5.8.4 2005-05-03 SHELL-QUOTE(1p)
All times are GMT -4. The time now is 07:31 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy