2. the process is not failing, it just give this error . (Note this error is not comming from code)
error: zipfile read error
(23409) Total records read 23897400
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,
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)
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)
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 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)
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)
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
LEARN ABOUT REDHAT
popen
POPEN(3) Linux Programmer's Manual POPEN(3)NAME
popen, pclose - process I/O
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 pipe, forking, and invoking the shell. Since a pipe is by definition unidirectional,
the type argument may specify only reading or writing, not both; the resulting stream is correspondingly read-only or write-only.
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 mode argument is a pointer to a null-terminated string which must be
either `r' for reading or `w' for writing.
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 com-
mand'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.
RETURN VALUE
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 wait4 returns an error, or some other error is detected.
ERRORS
The popen function does not set errno if memory allocation fails. If the underlying fork() or pipe() fails, errno is set appropriately.
If the mode argument is invalid, and this condition is detected, errno is set to EINVAL.
If pclose() cannot obtain the child status, errno is set to ECHILD.
CONFORMING TO
POSIX.2
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.
HISTORY
A popen() and a pclose() function appeared in Version 7 AT&T UNIX.
SEE ALSO fork(2), sh(1), pipe(2), wait4(2), fflush(3), fclose(3), fopen(3), stdio(3), system(3)BSD MANPAGE 1998-05-07 POPEN(3)