Sponsored Content
Top Forums UNIX for Dummies Questions & Answers How to write to stdin of another program (program A -> [stdin]program B) Post 302190772 by vvaidyan on Wednesday 30th of April 2008 12:36:39 PM
Old 04-30-2008
How to write to stdin of another program (program A -> [stdin]program B)

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[1], STDOUT_FILENO);
-> execl("/path/PROGRAM B", "PROGRAM B", NULL);

* parent
-> char line[100];
-> read(fd[0], line, 100);


Question:
---------
How to write to stdin of PROGRAM B from PROGRAM A?
* should I use a different pipe?
* how to I read stdin in PROGRAM B? using cin?

Thanks in advance,
Vivek
 

10 More Discussions You Might Find Interesting

1. Programming

How to write to stdin of another program (program A -> [stdin]program B)

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

How to clear the content of a pipe (STDIN) after it is written to another program?

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

C++ How to use pipe() & fork() with stdin and stdout to another program

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

A program to trace execution of another program

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

Script to open program and send/execute command in program

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

how to write next line program

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

Python program faster than C++ program.

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

Calling compiled C program with Perl program

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

How do you write this program/script?

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

Perl program get a response before the program quits

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
DIFF3(1)							   User Commands							  DIFF3(1)

NAME
diff3 - compare three files line by line SYNOPSIS
diff3 [OPTION]... MYFILE OLDFILE YOURFILE DESCRIPTION
Compare three files line by line. -e --ed Output unmerged changes from OLDFILE to YOURFILE into MYFILE. -E --show-overlap Output unmerged changes, bracketing conflicts. -A --show-all Output all changes, bracketing conflicts. -x --overlap-only Output overlapping changes. -X Output overlapping changes, bracketing them. -3 --easy-only Output unmerged nonoverlapping changes. -m --merge Output merged file instead of ed script (default -A). -L LABEL --label=LABEL Use LABEL instead of file name. -i Append `w' and `q' commands to ed scripts. -a --text Treat all files as text. -T --initial-tab Make tabs line up by prepending a tab. --diff-program=PROGRAM Use PROGRAM to compare files. -v --version Output version info. --help Output this help. If a FILE is `-', read standard input. AUTHOR
Written by Randy Smith. REPORTING BUGS
Report bugs to <bug-gnu-utils@gnu.org>. COPYRIGHT
Copyright (C) 2002 Free Software Foundation, Inc. This program comes with NO WARRANTY, to the extent permitted by law. You may redistribute copies of this program under the terms of the GNU General Public License. For more information about these matters, see the file named COPYING. SEE ALSO
The full documentation for diff3 is maintained as a Texinfo manual. If the info and diff3 programs are properly installed at your site, the command info diff should give you access to the complete manual. diffutils 2.8.1 April 2002 DIFF3(1)
All times are GMT -4. The time now is 08:54 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy