Date: Fri, 3 Jun 2005 19:55:29 -0400 From: Aziz Kezzou <french.linuxian@gmail.com> To: freebsd-hackers <freebsd-hackers@freebsd.org> Subject: Fork mystries.... Message-ID: <3727392705060316555071c4ad@mail.gmail.com>
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Hi all,
It's probably not the right mailing list to ask but I am really
surprised about global variable sharing in a multithreaded C
application. If I remember well my multithreading course global
variables are shared between threads, right ?
=20
Example :
----------------------------
int counter =3D 0;
int main() {
if( fork()=3D=3D0) {
while(1) {
sleep(1);
counter++;
printf("Son : counter =3D %d\n", counter); =20
} =20
} else {
while(1) {
sleep(1);
printf("Parent : counter =3D %d\n", counter); =20
}
}=09=20
return 0;
}
----------------------------
All I get is :
Parent : counter =3D 0
Son : counter =3D 1
Son : counter =3D 2
Parent : counter =3D 0
Son : counter =3D 3
Parent : counter =3D 0
Son : counter =3D 4
Parent : counter =3D 0
why counter isn't shared between the two threads ??!
thanks,
-aziz
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