Programming :: Psuedo Terminal - Cannot Add Fflush To Source Code

Feb 22, 2010

I have a problem in programing pseudo terminal. In the book APUE (advanced programing in the unix environment) in chapter 15.4: coprocess gives an example of using pipe to operate another program, that provide its input and read its output: Figure 15.18. Figure 15.19 is filter to add two numbers using standard IO. The author said that you must flush the IO buffer in the program which are operated through pipe by another program, however, we cannot add fflush to the source code and re-compile the whole program if we need to use it in another process. It said that pseudo terminal can solve this problem, but I have tried in fedora12 with forkpty call and fail. Source code as follows:

The main process:
Code:
#include "common.h"
#define LINESIZE 256
int main()
{
int fd[2];
pid_t pid;
if( socketpair(AF_UNIX, SOCK_STREAM, 0, fd)<0 ) {
perror("create socket error");
exit(1);
}
int master;
struct termios tm;
if( tcgetattr(STDIN_FILENO, &tm)<0 ) {
perror("tcgetattr error");
exit(3);
}
struct winsize size;
if( ioctl(STDIN_FILENO, TIOCGWINSZ, (char*)&size)<0 ) {
perror("ioctl error");
exit(4);
}
setbuf(stdout, NULL);
pid=forkpty(&master, NULL, &tm, &size);
if( pid<0 ) {
perror("create process error");
exit(2);
}
else if(pid>0) {//parent
close(fd[1]);
char line[LINESIZE];
memset(line, 0, LINESIZE);
while( fgets(line, LINESIZE, stdin)!=NULL ) {
write(fd[0], line, strlen(line));
memset(line, 0, LINESIZE);
int n=read(fd[0], line, LINESIZE);
if(n>=0) line[n]=0;
printf("%s", line);
memset(line, 0, LINESIZE);
}
} else {//child
close(fd[0]);
if( fd[1]!=STDIN_FILENO ) {
if(dup2(fd[1], STDIN_FILENO)!=STDIN_FILENO) {
perror("dup2 error");
exit(1);
}
}
if( fd[1]!=STDOUT_FILENO) {
if(dup2(fd[1], STDOUT_FILENO)!=STDOUT_FILENO) {
perror("dup2 error");
exit(2);
}
}
close(fd[1]);
if(execl("./add", "add", (char*)0)<0) {
perror("exec error");
exit(3);
}
exit(0);
}
//parent
wait(NULL);
return 0;
}
The add program reads a line and get two numbers and return the sum of them.

Code:
#include "common.h"
int main() { int n1, n2;
char line[256];
memset(line, 0, 256);
while( fgets(line, 256, stdin)!=NULL) {
sscanf(line, "%d%d", &n1, &n2);
printf("%d", n1+n2);
fflush(NULL); /*the program does not work without this sentence why?*/
memset(line, 0, 256); } return 0; }

View 5 Replies


ADVERTISEMENT

General :: Keyboard Does Not Work In **Ubuntu Terminal **whilst Writing A Source Code?

Aug 29, 2010

I have installed a Virtual machine.I use Virtual Box for the same. My host OS is Windows XP SP3. I have assigned it 500mb of Ram and it works fine. But my problem is that my Keyboard does not work in Ubuntu terminal whilst writing a source code.

When I use the arrow keys it gives me alphabets A B C D. And also when i press a . it acts as a backspace.I have a cordless Logitech Keyboard.I don't know why my keyboard isn't functioning inside the Terminal (& that to only whilst typing in source codes) I have tried changing the Character Encoding but thats not helping.

View 2 Replies View Related

Ubuntu Installation :: Compileing The Source Code In The Terminal - Cannot Open: No Such File Or Directory

Apr 13, 2011

I've tried a couple times to install from a tar.gz file and when i try to compile the source code in the terminal I get this error "tar: bash-4.2.tar.gz: Cannot open: No such file or directory" what am I doing wrong? Now when I download the files, I leave themin the down loads folder, do i need to make a new directory? If so how do I do that and how do i call it up when I compile the sopurce?

View 1 Replies View Related

Programming :: App To Annotate Source Code ?

May 11, 2010

I've tried to use google to find this, and all I find is M$ SAL and some annotation standard for java, neither of which is anything like what I'm looking for.

I am pouring over someone else's source code, and want to be able to take notes on it, saving those notes in a separate text file that I can grep, open in a text editor, etc. I want each annotation line to include a line number (or range of lines) so it's easy to know what part of the code it refers to.

I could do this by hand, but it would be nice if a program existed to read and write such a file format. It could be similar to Kompare, only with editable notes on one side and source on the other, linked together with colored bands.

Does such a thing exist?

Cosme Zamudio and I are discussing a possible file format and an Android app - [url]

View 4 Replies View Related

Programming :: 'Top' Command Source Code

Jan 19, 2010

Where can I find the top command source code... I got it from "http://procps.sourceforge.net/index.html" but it seems for Solaris. where can I get the source code for top commend running on Linux????

View 3 Replies View Related

Programming :: Where Is The Kernel Source Code ?

Mar 7, 2011

In particular i'd like to know where is the kernel source code in slackware 13.

View 2 Replies View Related

Programming :: Source Code On Email Parsing In C++ ?

May 11, 2010

Does anyone have source code on Email parsing in C++

View 1 Replies View Related

Programming :: Debugging Nasm Source Code ?

Dec 5, 2010

I found on the Internet a rough suggestion to debug code which says to add a line:

An example shows this lists the lines of source that do work.

I do not know where these lines are supposed to go and whether the "notdeadyet" should be a call to a subroutine or what. I only found that "%define" is used to link to external files, so I am confused because what I tried did not work.

(I am unable to use (and learn) any debugging tool for another few weeks and I'd like to progress on this If I can.)

View 2 Replies View Related

Programming :: How To Get Source Code Of Command Line?

Jan 23, 2009

I just want to see how the command line such as : "cat", "split", "ls"...ect source code ? Are they written in C or other language ? I don't know where to search those?

View 6 Replies View Related

Programming :: Analyzing USB Driver Source Code?

Nov 29, 2010

For one of my class projects, we have to analyze a usb keyboard driver source code and be able to understand it and present it to the class. Me and a few other people are working together by breaking up the code into sections so each person can analyze a section of code.Now I've ran into a section of this code that I am a little confused about. It seems fairly simple but I just wanted to double check since I wasn't able to find a solid answer.

Code:
static const unsigned char usb_kbd_keycode[256] = {
0, 0, 0, 0, 30, 48, 46, 32, 18, 33, 34, 35, 23, 36, 37, 38,

[code]....

View 10 Replies View Related

Programming :: Source Code For Cd - Change Directory

Feb 9, 2010

I want to modify the source of cd (the 'change directory' command) to do a little extra for me, but I can't seem to find the source code anywhere.. maybe I didn't look for it well enough, and googling "source code cd" and variants of that doesn't exactly help... I was wondering if anyone knew where I could find the src?

View 14 Replies View Related

Programming :: Where To Get Source Code Of Quick Thread?

Mar 25, 2011

Where can I get the source code of quick thread?

View 1 Replies View Related

Programming :: Interact With The File System By Own C Source-code?

Jun 1, 2010

I'm investigating how to copy a file located in my file system into another device. I googled to find a solution for my case but I didn't find anything. My original problem was to find a way to permit my code to move a file into a USB device. I wonder If is there a way to implement the cp command or some mechanism that permits my code to interact with between the file system on my computer and the second one on USB external driver (FAT32) ?

View 3 Replies View Related

Programming :: Attach Source Code To A Remote Debug?

May 25, 2011

running a java application in a remote site,and I would like to debug the application. I'm using jdb, and, due to network architecture, I can only use jdb do debug in text-mode. To debug in text-mode I use the command: jdb -attach remotesite: port. At this point this is ok. Now I would like to attach the source code to the jdb. I tried the command

jdb -attach remotesite: port ~/src/org/path/file.java

to attach the source code to the remote debug to. But it doesn't work. In jdb, I try the command use ~/src/org/path/file.java but it doesn't work either. How can I attach the source code to the remote debug?

View 1 Replies View Related

Programming :: Compilling C++ Source Code (class) Error?

Feb 24, 2011

please i try to compile the below code on ubuntu with g++ but i was getting an error message

fig03_05.cpp:10: error: new types may not be defined in a return type
fig03_05.cpp:10: note: (perhaps a semicolon is missing after the definition of �GradeBook�)
fig03_05.cpp:32: error: two or more data types in declaration of �main�

[code]...

View 7 Replies View Related

Programming :: Creating Setup File From Source Code?

Jun 30, 2011

I had made some modifications in the source code of a software called "HomeBank". I'm not able to make a setup file using "Inno setup".how to create an .EXE file for the source code to execute.

View 2 Replies View Related

Programming :: Create A .bin File From Java Source Code?

Jan 4, 2010

i am trying to generate a linux executable data (bin data) from my java source code.

View 4 Replies View Related

Programming :: Transmit A File By Source-code To USB Drive?

Jun 1, 2010

I want to find a simple and quick way to permit my application to bring a file located in my file system and write it into an external USB device. I have to use Bulk Transfer Only mode that means to use stream of characters only. I looked through the LibUsb library using it in my IDE I can transmit a string. To transfer a whole file I suppose I've to dodge the file system building a char sequence that permits to recognise a file in the file system and to put it into the usb device.

View 1 Replies View Related

Programming :: Locating Copy & Paste Source Code?

Mar 20, 2011

I've never really taken advantage of Linux being open source before but I was wondering how the copy and paste functions look like. So far I have found out that they are handled by the X Window System (by reading this thread).But I don't seem to get much further than that.

View 1 Replies View Related

Programming :: Point Out The The Source Code For Page Swapping?

Apr 9, 2010

I am doing a project on page replacement algorithms.... Can anyone point out the the source code for page swapping in linux kernel source tree.(I am using 2.6.31 kernel on a 32 bit x86 machine).

View 1 Replies View Related

Programming :: Can Bash Commands Be Converted To Assembly Like C Source Code?

Nov 30, 2010

I have read where C is first converted to Assembly before its final compilation to binary. Is there a way to do this with Bash commands? I would like the understanding that Assembly allows to Bash somehow.

View 14 Replies View Related

Programming :: GDB Doesn't Provide The Correct Line In The Source Code

Jan 23, 2011

I found a strange problem when I use gdb in eclipse to debug. When I step in the program, the register RIP(I'm using x86_64 machine and that's EIP in 32 bit mode) shows correctly but the line stepping in the source code may be far from the correct line. For example, when there is no loop in the source code, the RIP keeps on increasing and the current instruction pointer goes back to several lines back. I'm sure the source code is the right one because I when I checked the memory and local variables after several lines the values are all correct. The source code has many empty lines and does it matters with GDB?

View 3 Replies View Related

Programming :: How To Edit Kernel Source Code In MS Visual Studio

Apr 27, 2010

I want to edit linux kernel source code in MS Visual Studio. I saw the code and these are c files but there is no project file that i open it and whole project opens up. I can open each individual file but not the whole project.

View 13 Replies View Related

Programming :: Kill Follow-on Code If Source Fails In Bash?

Dec 20, 2009

I have a Bash script that runs other bash scripts. If the parent code fails, is there any way for me to also kill the child code?That kills any multiple instances of a script if I run it more than once. Is there any way I can just modify this into something that prevents the child code from running/continuing from running if the parent stops from an error?

View 3 Replies View Related

Programming :: Script - Which Shows Https Page Source Code

Feb 22, 2010

I would like to download and show a source of an webpage in stdout, but this is a https page with authentication form, which requires logging in. I tried like this:

Code:
wget -q --no-check-certificate --http-user=USERNAME --http-password=PASSWORD https://webpage.domain.com -O - However, it still downloaded only this login page, not the real webpage. Using the Firefox I can authenticate just fine. Any ideas?

View 5 Replies View Related

Programming :: Find Source Code Of C Library Files In Ubuntu?

Feb 26, 2009

Where do i found source code of c library files in ubuntu.

View 2 Replies View Related

Programming :: Source Code To Get The Location Of Installed Files After Rpm Installation

Jul 25, 2011

The rpm command to get all the list of all installed file location after rpm installation is rpm -ql <rpm file-name>

View 7 Replies View Related

Programming :: Cannot Compile C++ Code In Terminal

Feb 13, 2011

I am unable to compile C++ program in terminal. Whenever I try to add "#include<iostream.h>" it shows an error and thats why I can not use "cout" and "cin" functions. I installed g++ for this but the problem persists.

View 4 Replies View Related

Ubuntu :: Source Code Of The Krnel From The Kernel.org - Source Trees Organization

Apr 11, 2011

i am already a little bit familiar with linux and now i want to know better the linux OS. i have downloaded the source code of the krnel from the kernel.org and i dont understand the linux source trees organization, so can somebody do me a favor and give me a link to some internet page (or at least a book) that explains that?? i have searched in the internet with the tag:::linux source trees organization and i have not found nothing interesting

View 1 Replies View Related

Ubuntu :: How To See Source Code Of Open Source Software

Sep 12, 2010

I want to see the source code of smplayer software.from where i can see source code of open source softwares?

View 9 Replies View Related







Copyrights 2005-15 www.BigResource.com, All rights reserved