Maybe there's more than 512 bytes of output, and you're forcing it to close before it's finished? This will break the pipe, causing it to get the signal SIGPIPE which will kill it prematurely, which will give you a weird exit code.
You can also use the fread command since you've converted it to a FILE * anyway.
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)
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 CENTOS
fwrite
FREAD(3) Linux Programmer's Manual FREAD(3)NAME
fread, fwrite - binary stream input/output
SYNOPSIS
#include <stdio.h>
size_t fread(void *ptr, size_t size, size_t nmemb, FILE *stream);
size_t fwrite(const void *ptr, size_t size, size_t nmemb,
FILE *stream);
DESCRIPTION
The function fread() reads nmemb elements of data, each size bytes long, from the stream pointed to by stream, storing them at the location
given by ptr.
The function fwrite() writes nmemb elements of data, each size bytes long, to the stream pointed to by stream, obtaining them from the
location given by ptr.
For nonlocking counterparts, see unlocked_stdio(3).
RETURN VALUE
On success, fread() and fwrite() return the number of items read or written. This number equals the number of bytes transferred only when
size is 1. If an error occurs, or the end of the file is reached, the return value is a short item count (or zero).
fread() does not distinguish between end-of-file and error, and callers must use feof(3) and ferror(3) to determine which occurred.
CONFORMING TO
C89, POSIX.1-2001.
SEE ALSO read(2), write(2), feof(3), ferror(3), unlocked_stdio(3)COLOPHON
This page is part of release 3.53 of the Linux man-pages project. A description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
GNU 2012-03-30 FREAD(3)