08-02-2008
Also note: popen is a one way deal - you choose either to write to or to read from a child process, popen will not let you do both at the same time. Otherwise, you get into more interesting and advanced interprocess communication (IPC) programming like maybe pipes.
10 More Discussions You Might Find Interesting
1. Programming
Hi,
Program A: uses pipe()
I am able to read the stdout of PROGAM B (stdout got through system() command) into PROGRAM A using:
* child
-> dup2(fd, STDOUT_FILENO);
-> execl("/path/PROGRAM B", "PROGRAM B", NULL);
* parent
-> char line;
-> read(fd, line, 100);
Question:
---------... (1 Reply)
Discussion started by: vvaidyan
1 Replies
2. Programming
PROGRAM A <-> PROGRAM B
PROGRAM A sends data as STDIN ro PROGRAM B and when PROGRAM B is executed from PROGRAM A, it sends output back to PROGRAM A. This is implemented using 2 pipes (fd1 & fd2).
The above process happens in a loop and during the second run, the previous data that had been... (10 Replies)
Discussion started by: vvaidyan
10 Replies
3. Programming
Hi,
Program A: uses pipe()
I am able to read the stdout of PROGAM B (stdout got through system() command) into PROGRAM A using:
* child
-> dup2(fd, STDOUT_FILENO);
-> execl("/path/PROGRAM B", "PROGRAM B", NULL);
* parent
-> char line;
-> read(fd, line, 100);
Question:... (2 Replies)
Discussion started by: vvaidyan
2 Replies
4. Programming
Hi,
I wanted to know if i can write a program using switches and signals, etc to trace execution of other unix program which calls c program internally.
If yes how? If not with signals and switches then are there any other methods apart from debugging with gdb/dbx. (3 Replies)
Discussion started by: jiten_hegde
3 Replies
5. UNIX for Dummies Questions & Answers
Hi,
i want to write a script that executes a program (exec?) .
this program then requires a filename as input.
how do i give it this input in the script so the program will be complete run and close by the script.
e.g.
exec prog.exe
program then asks for filename
"enter filename:"... (1 Reply)
Discussion started by: tuathan
1 Replies
6. Shell Programming and Scripting
Hi,
I am having an input file which contains a group of words,if one specific word comes which goes to next line.
example:
input file===>
shashi country= india comapny= none shashi shashi company= NONE shashi=my name
output===>
shashi country= india comapny= none
shashi
shashi... (6 Replies)
Discussion started by: hegdeshashi
6 Replies
7. Programming
I wrote a simple program that generates a random word 10,000,000 times.
I wrote it in python, then in C++ and compared the two completion times. The python script was faster! Is that normal? Why would the python script be faster? I was under the impression that C++ was faster. What are some of... (2 Replies)
Discussion started by: cbreiny
2 Replies
8. Homework & Coursework Questions
Long story short: I'm working inside of a Unix SSH under a bash shell. I have to code a C program that generates a random number. Then I have to call the compiled C program with a Perl program to run the C program 20 times and put all the generated random #s into a text file, then print that text... (1 Reply)
Discussion started by: jdkirby
1 Replies
9. Shell Programming and Scripting
I need help with the following.
1) Write a program in any language that takes a single integer array parameter and returns the decimal average of the input values.
2) Write a program, in any language, that prints the integers from 1 to 10, along with a cumulative sum of the integers printed... (1 Reply)
Discussion started by: sqa4life
1 Replies
10. Shell Programming and Scripting
I created a program, so a kid can practice there math on it. It dispenses varies math problems and the kid must input an answer. I also want it to grade the work they have done, but I can't find the best place for it to print out the grade.
I have:
if ( $response =~ m/^/ ) {
$user_wants_to_quit... (1 Reply)
Discussion started by: germany1517
1 Replies
pclose(3) Library Functions Manual pclose(3)
NAME
pclose - Closes a pipe to a process
LIBRARY
Standard C Library (libc.so, libc.a)
SYNOPSIS
#include <stdio.h>
int pclose (
FILE *stream );
STANDARDS
Interfaces documented on this reference page conform to industry standards as follows:
pclose(): XPG4, XPG4-UNIX
Refer to the standards(5) reference page for more information about industry standards and associated tags.
PARAMETERS
Points to a FILE structure for an open pipe returned by a previous call to the popen() function.
DESCRIPTION
The pclose() function closes a pipe between the calling program and a shell command to be executed. Use the pclose() function to close any
stream you have opened with the popen() function. The pclose() function waits for the associated process to end, and then returns the exit
status of the command. If the original processes and the process started with the popen() function concurrently read or write a common
file, neither should use buffered I/O. If they do, the results are unpredictable.
RETURN VALUES
Upon successful completion, the pclose() function returns the exit status of the command.
If an error is detected, pclose() sets errno to an appropriate value and returns a value of -1.
ERRORS
If the pclose() function fails, errno may be set to the following value: The status of the child process could not be obtained.
RELATED INFORMATION
Functions: fclose(3), popen(3), wait(2)
Standards: standards(5) delim off
pclose(3)