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:

#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

when you run that program it is a process and it is a new thread(AFAIK)
this sounds suspiciously like homework

Originally Posted by AceofSpades19 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

Originally Posted by raedbenz 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

#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

Originally Posted by AceofSpades19 and it is a new thread(AFAIK) k

well some processes have more than thread ,isn't it?
like what?

Originally Posted by raedbenz 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

HI,
sigaction() is system call or API?
setitimer() is system call or API?

thanks

Originally Posted by raedbenz 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

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

sigaction() is part of the c library and setitimer() is a system call

and, incidentally, system() is in fact a library call, not a system call

HI chrism,

AceofSpace19 said

#include <stdio.h> int main(void){ system("echo hello"); return 0; } that creates a system call

Originally Posted by chrism01 and, incidentally, system() is in fact a library call, not a system call

How ?

Originally Posted by chrism01 and, incidentally, system() is in fact a library call, not a system call

really?, I read that it was a system call

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

man man

System calls are documented in section 2, C libaray function in section 3.

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