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Full Discussion: [C] exec system call
Top Forums Programming [C] exec system call Post 302581163 by lamachejo on Monday 12th of December 2011 08:56:20 AM
Old 12-12-2011
[C] exec system call

Hi again Smilie Now I want to make a program that will execute the programs with exec, asking the user if he wants the program to run in background or foreground.

Code:
scanf("%c",&caracter);
if (caracter=='y'){
	printf("Has decidido ejecutarlo en background\n");
	if((pid=fork())==0) {// fork para ejecutar en bg
		for (i=1; i<argc; i++)
			execl(argv[i],argv[i], 0);
		exit(0);
	}
}
else	{
	printf("Has decidido ejecutarlo en foreground\n");
	for (i=1; i<argc; i++)
		execl(argv[i],argv[i], 0);
	}

Problem is, it will only execute 1 program. If i try to write ./execute /bin/ls /bin/ls only once will be shown. What's worse, when I try to debug it with ddd, ddd will also crash with a segmentation fault (this happens on foreground code). Smilie

Edit: related topics below my post may have given me the answer: is it because when you call exec(), the code of my program won't execute any more?

Last edited by lamachejo; 12-12-2011 at 10:39 AM..
 

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DH-EXEC-ILLITERATE(1)						      dh-exec						     DH-EXEC-ILLITERATE(1)

NAME
dh-exec-illiterate - Write literate debhelper config files! SYNOPSIS
#! /usr/bin/dh-exec --with=illiterate,subst,install Greetings, my dear reader, and welcome to the awesome world of literate programming! Today, we're going to explore how to write a debhelper install file in a literate manner. Trust me, it's going to be lots and lots of fun! So, what exactly are we trying to accomplish? We're going to try installing a file from `src/this-file' in the source tree, to a multi-arched path in the binary file. Lets say, to `/usr/lib/foo/${DEB_HOST_MULTIARCH}/'. Of course, ${DEB_HOST_MULTIARCH} is a variable, and will be expanded later in the dh-exec pipeline. It'll be something like x86_64-linux-gnu. Furthermore, we want to install all files from the 'usr/lib' directory under debian/tmp. If we were writing an illiteral install file, we'd write this rule as: usr/lib But the above description is much easier to understand, isn't it? We're almost finished! One thing left to do, is to install a script named `rename-me', to `/usr/share/foo/new-name' - we renamed it in the process! DESCRIPTION
The dh-exec-illiterate sub-command, unlike the others, does not serve any particular case, except to serve as a warning to all, that things can be taken to an extreme, even with dh-exec. On the other hand, it is just like the other sub-commands in that it must not be called directly, but through dh-exec(1), which automatically runs all available sub-commands if run bare; or explicitly with dh-exec --with=illiterate. It is a program that will translate its input from pretty much free-form text into something that resembles an install file. At least, that's the only supported output format for now. Everything that's not recognised, will be ignored, and not printed. The recognised constructs are: `source' ... `destination' The first string between a backtick and a single quote will be treated as the source file, the next such string will be the destination. If the destination ends with a slash, dh-exec-illiterate will consider it a directory, otherwise it will output a construct that dh-exec-install can recognise as a rename operation. 'source' A string, without whitespace, between two single quotes is treated as a source, whose destination is unspecified, and is left up to dh_install(1) to figure out. ENVIRONMENT
DH_EXEC_SCRIPTDIR Indicates which directory the command-specific scripts should be sought for. If not specified, scripts will be searched for in /usr/share/dh-exec/. FILES
$DH_EXEC_SCRIPTDIR/dh-exec-illiterate-* The various scripts for the higher-level program. SEE ALSO
debhelper(1), dh-exec(1) AUTHOR
dh-exec-illiterate is copyright (C) 2011-2012 by Gergely Nagy <algernon@madhouse-project.org>. 2012-05-03 DH-EXEC-ILLITERATE(1)
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