Hi again 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).
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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Discussion started by: demis87
2 Replies
LEARN ABOUT V7
fork
FORK(2) System Calls Manual FORK(2)NAME
fork - spawn new process
SYNOPSIS
fork( )
DESCRIPTION
Fork is the only way new processes are created. The new process's core image is a copy of that of the caller of fork. The only distinc-
tion is the fact that the value returned in the old (parent) process contains the process ID of the new (child) process, while the value
returned in the child is 0. Process ID's range from 1 to 30,000. This process ID is used by wait(2).
Files open before the fork are shared, and have a common read-write pointer. In particular, this is the way that standard input and output
files are passed and also how pipes are set up.
SEE ALSO wait(2), exec(2)DIAGNOSTICS
Returns -1 and fails to create a process if: there is inadequate swap space, the user is not super-user and has too many processes, or the
system's process table is full. Only the super-user can take the last process-table slot.
ASSEMBLER
(fork = 2.)
sys fork
(new process return)
(old process return, new process ID in r0)
The return locations in the old and new process differ by one word. The C-bit is set in the old process if a new process could not be cre-
ated.
FORK(2)
12-12-2011
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.