I am trying to use popen function with wrtie option to give inputs to ftp command.
So when i execute this with following inputs at stdin, it should give these lines to ftp as input. But it isn't working as i expected.
the input is
-bash-3.1$ ./a.out
open localhost
user
password
get /tmp/test_file
bye
^D (interrupt)
Please help me on this.
---------- Post updated at 03:37 PM ---------- Previous update was at 01:46 PM ----------
Sorry for the blunder mistakes i have made..
I have managed to figure out the issues.
THis code has worked
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)
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)
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)
Hi all,
In my application i am trying to select some text & then give it to print. for this i am opening a stream using popen & then later closing using pclose.
Now this is working fine in my environment (solaris) but the pclose function is failing at my clients m/c. Even though print is... (3 Replies)
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)
Hi,
I am having a hell of a time getting this to work. So basically, I have opened a popen to run a program that is going to prompt an action to occur half way through, when it gets to this I need to create a separate process and do some stuff, then return to the original process. This works... (0 Replies)
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)
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
LEARN ABOUT FREEBSD
popen
POPEN(3) BSD Library Functions Manual POPEN(3)NAME
popen, pclose -- process I/O
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <stdio.h>
FILE *
popen(const char *command, const char *type);
int
pclose(FILE *stream);
DESCRIPTION
The popen() function ``opens'' a process by creating a bidirectional pipe forking, and invoking the shell. Any streams opened by previous
popen() calls in the parent process are closed in the new child process. Historically, popen() was implemented with a unidirectional pipe;
hence many implementations of popen() only allow the type argument to specify reading or writing, not both. Since popen() is now implemented
using a bidirectional pipe, the type argument may request a bidirectional data flow. The type argument is a pointer to a null-terminated
string which must be 'r' for reading, 'w' for writing, or 'r+' for reading and writing.
A letter 'e' may be appended to that to request that the underlying file descriptor be set close-on-exec.
The command argument is a pointer to a null-terminated string containing a shell command line. This command is passed to /bin/sh using the
-c flag; interpretation, if any, is performed by the shell.
The return value from popen() is a normal standard I/O stream in all respects save that it must be closed with pclose() rather than fclose().
Writing to such a stream writes to the standard input of the command; the command's standard output is the same as that of the process that
called popen(), unless this is altered by the command itself. Conversely, reading from a ``popened'' stream reads the command's standard
output, and the command's standard input is the same as that of the process that called popen().
Note that output popen() streams are fully buffered by default.
The pclose() function waits for the associated process to terminate and returns the exit status of the command as returned by wait4(2).
RETURN VALUES
The popen() function returns NULL if the fork(2) or pipe(2) calls fail, or if it cannot allocate memory.
The pclose() function returns -1 if stream is not associated with a ``popened'' command, if stream already ``pclosed'', or if wait4(2)
returns an error.
ERRORS
The popen() function does not reliably set errno.
SEE ALSO sh(1), fork(2), pipe(2), wait4(2), fclose(3), fflush(3), fopen(3), stdio(3), system(3)HISTORY
A popen() and a pclose() function appeared in Version 7 AT&T UNIX.
Bidirectional functionality was added in FreeBSD 2.2.6.
BUGS
Since the standard input of a command opened for reading shares its seek offset with the process that called popen(), if the original process
has done a buffered read, the command's input position may not be as expected. Similarly, the output from a command opened for writing may
become intermingled with that of the original process. The latter can be avoided by calling fflush(3) before popen().
Failure to execute the shell is indistinguishable from the shell's failure to execute command, or an immediate exit of the command. The only
hint is an exit status of 127.
The popen() function always calls sh(1), never calls csh(1).
BSD May 20, 2013 BSD