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Old 07-12-2008, 02:27 PM   #1
raedbenz
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process ,threads and system calls


Hi,
i am newbit to Linux. i have been reading many books and tutorials online about kernel and etc....
i feel like still i need a solid and simple example, that shows the difference among the three terms (process ,threads and system calls).
if we assume this "hello world" code:
Code:
#include <stdio.h>

int main(void)
{
	printf("Hello World");
	
	return 0;
}
In the above code which is the process? which is the thread and which the system call?
if u have a better example plz post it.
thanks
 
Old 07-12-2008, 02:47 PM   #2
AceofSpades19
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when you run that program it is a process and it is a new thread(AFAIK)
this sounds suspiciously like homework
 
Old 07-12-2008, 02:52 PM   #3
raedbenz
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Quote:
Originally Posted by AceofSpades19 View Post
when you run that program it is a process and it is a new thread(AFAIK)
this sounds suspiciously like homework
lol, actually its not homewrok,
where is the system call in here?
any better examples?
more over POSIX or ANSI C functions (like sigaction(),setitimer(),mmap() etc...)are considered threads or what?

thanks
 
Old 07-12-2008, 03:01 PM   #4
AceofSpades19
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Quote:
Originally Posted by raedbenz View Post
lol, actually its not homewrok,
where is the system call in here?
any better examples?
more over POSIX or ANSI C functions (like sigaction(),setitimer(),mmap() etc...)are considered threads or what?

thanks
Code:
#include <stdio.h>


int main(void){
system("echo hello");
return 0;
}
that makes a system call
a function call does not normally make a new thread
 
Old 07-12-2008, 03:09 PM   #5
raedbenz
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Quote:
Originally Posted by AceofSpades19 View Post
and it is a new thread(AFAIK)
k
well some processes have more than thread ,isn't it?
like what?
 
Old 07-12-2008, 03:57 PM   #6
AceofSpades19
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Quote:
Originally Posted by raedbenz View Post
well some processes have more than thread ,isn't it?
like what?
yes, a process can have more then one thread. Here are some links about threading
http://www.ibm.com/developerworks/library/l-posix1.html
http://arstechnica.com/articles/paed...rthreading.ars
 
Old 07-12-2008, 04:01 PM   #7
raedbenz
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HI,
sigaction() is system call or API?
setitimer() is system call or API?

thanks
 
Old 07-12-2008, 04:29 PM   #8
AceofSpades19
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Quote:
Originally Posted by raedbenz View Post
HI,
sigaction() is system call or API?
setitimer() is system call or API?

thanks
if you google those, I'm sure the results will tell you what they are
 
Old 07-12-2008, 04:31 PM   #9
raedbenz
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lol,
if i had not googled, then i would post a thread from the begging.
But bcoz i have some misconceptions thats y i posted this thread.
Unless u dont know the answer
 
Old 07-12-2008, 04:59 PM   #10
AceofSpades19
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sigaction() is part of the c library and setitimer() is a system call
 
Old 07-14-2008, 02:56 AM   #11
chrism01
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and, incidentally, system() is in fact a library call, not a system call
 
Old 07-14-2008, 03:06 AM   #12
raedbenz
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HI chrism,

AceofSpace19 said
Quote:
Code:
#include <stdio.h>
int main(void){
system("echo hello");
return 0;
}
that creates a system call
Quote:
Originally Posted by chrism01 View Post
and, incidentally, system() is in fact a library call, not a system call
How ?
 
Old 07-14-2008, 03:24 AM   #13
AceofSpades19
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Quote:
Originally Posted by chrism01 View Post
and, incidentally, system() is in fact a library call, not a system call
really?, I read that it was a system call
 
Old 07-14-2008, 05:10 AM   #14
fbianconi
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http://www.cs.cf.ac.uk/Dave/C/ this is a good book you can get started with.
Is from University of Leeds, and has an ugly copyright, but still readable online.
here can found more:
http://en.wikibooks.org/wiki/Programming:C
sorry can't edit links on ephy
 
Old 07-14-2008, 08:16 AM   #15
smoked kipper
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Code:
man man
System calls are documented in section 2, C libaray function in section 3.

Quote:
MANUAL SECTIONS
The standard sections of the manual include:

1 User Commands
2 System Calls
3 C Library Functions
4 Devices and Special Files
5 File Formats and Conventions
6 Games et. Al.
7 Miscellanea
8 System Administration tools and Deamons
 
  


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