when we fork a new process, parent gets the PID of the chid as return value and child will get 0 as return value. Same address space is copied and both of them start executing this program in their own address space. In Modern OSes 99% of the time child comes first so child process is execute else part and parent will execute if place.
On Fri, Jun 3, 2011 at 10:58 PM, nicks <[email protected]> wrote: > i mean why both the if else statements are working by using fork ? > > On Fri, Jun 3, 2011 at 10:20 AM, Naveen Kumar > <[email protected]>wrote: > >> Process don't share address space when forked. >> >> >> >> On Fri, Jun 3, 2011 at 10:40 PM, nitish goyal <[email protected]>wrote: >> >>> @ Lalit >>> You are right. >>> >>> that's why i am saying how i can use semaphores in the above example >>> >>> >>> On Fri, Jun 3, 2011 at 10:37 PM, LALIT SHARMA <[email protected]>wrote: >>> >>>> While using fork(), child shares parent address space , >>>> >>>> Correct me If I am wrong .. >>>> >>>> On Fri, Jun 3, 2011 at 10:28 PM, nitish goyal <[email protected]> >>>> wrote: >>>> > Hi all, >>>> > >>>> > I am stuck with this code..Can anyone tell me how to implement >>>> semaphores in >>>> > fork system call >>>> > Code: >>>> > >>>> > #include<stdio.h> >>>> > >>>> > int signal(int *n); >>>> > int wait(int *n); >>>> > >>>> > >>>> > int main() >>>> > { >>>> > int n; >>>> > n=0; >>>> > if(fork()) >>>> > { >>>> > printf("Hello"); >>>> > signal(&n); >>>> > } >>>> > else >>>> > { >>>> > wait(&n); >>>> > printf("World"); >>>> > } >>>> > } >>>> > int signal(int *n) >>>> > { >>>> > (*n)++; >>>> > } >>>> > int wait(int *n) >>>> > { >>>> > while((*n)<=0); >>>> > (*n)--; >>>> > } >>>> > >>>> > Since parent process and child process will be having different >>>> address >>>> > spaces...so change of n in one address space will not be visible to >>>> other.so >>>> > please tell me how to make n visible to both the processes >>>> > >>>> > On Fri, Jun 3, 2011 at 2:45 PM, Subhransu < >>>> [email protected]> >>>> > wrote: >>>> >> >>>> >> Here you go in C code >>>> >> http://codepad.org/gk6AZj0T >>>> >> >>>> >> >>>> >> int main() >>>> >> { >>>> >> if(printf("hello")!=0) { >>>> >> printf("world"); >>>> >> } >>>> >> else { >>>> >> printf("SCREWED ! ! !"); } >>>> >> >>>> >> return 0; >>>> >> } >>>> >> >>>> >> >>>> >> Subhransu Panigrahi >>>> >> >>>> >> Mobile: +91-9840931538 >>>> >> Email: [email protected] >>>> >> >>>> >> >>>> >> On Fri, Jun 3, 2011 at 1:57 PM, Naveen Kumar < >>>> [email protected]> >>>> >> wrote: >>>> >>> >>>> >>> Hi Shachindra, >>>> >>> I don't think letters will be jumbled because we a calling one api >>>> to >>>> >>> output on console & tty's driver takes whole line and output it at >>>> once. >>>> >>> >>>> >>> On Fri, Jun 3, 2011 at 12:40 PM, Vishal Thanki < >>>> [email protected]> >>>> >>> wrote: >>>> >>>> >>>> >>>> @sachindra, @naveen, >>>> >>>> this was just a plain trick to execute "if" and "else" block. i >>>> agree >>>> >>>> with your concerns :) >>>> >>>> >>>> >>>> 2011/6/3 Vιиodh <[email protected]>: >>>> >>>> > @vishal: >>>> >>>> > can u explain the fork() solution?? >>>> >>>> > >>>> >>>> > On Fri, Jun 3, 2011 at 12:16 PM, Shachindra A C >>>> >>>> > <[email protected]> >>>> >>>> > wrote: >>>> >>>> >> >>>> >>>> >> There can be some synchronisation problems with fork() right? >>>> say >>>> >>>> >> world >>>> >>>> >> might get printed first...or maybe the letters can get jumbled >>>> >>>> >> too...We >>>> >>>> >> cannot guarantee the order of execution unless we use >>>> semaphores. >>>> >>>> >> >>>> >>>> >> On Fri, Jun 3, 2011 at 12:14 PM, Naveen Kumar >>>> >>>> >> <[email protected]> >>>> >>>> >> wrote: >>>> >>>> >>> >>>> >>>> >>> oh yes, >>>> >>>> >>> gud one >>>> >>>> >>> >>>> >>>> >>> On Fri, Jun 3, 2011 at 12:12 PM, Vishal Thanki >>>> >>>> >>> <[email protected]> >>>> >>>> >>> wrote: >>>> >>>> >>>> >>>> >>>> >>>> vishal@ubuntu:~/progs/c\ 12:11:53 PM >$ cat fork.c >>>> >>>> >>>> #include <stdio.h> >>>> >>>> >>>> #include <stdlib.h> >>>> >>>> >>>> >>>> >>>> >>>> int main() >>>> >>>> >>>> { >>>> >>>> >>>> if (fork()) { >>>> >>>> >>>> printf("hello "); >>>> >>>> >>>> } else { >>>> >>>> >>>> printf("world\n"); >>>> >>>> >>>> } >>>> >>>> >>>> return 0; >>>> >>>> >>>> } >>>> >>>> >>>> vishal@ubuntu:~/progs/c\ 12:11:56 PM >$ gcc fork.c >>>> >>>> >>>> vishal@ubuntu:~/progs/c\ 12:12:06 PM >$ ./a.out >>>> >>>> >>>> hello world >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> On Fri, Jun 3, 2011 at 12:09 PM, Naveen Kumar >>>> >>>> >>>> <[email protected]> wrote: >>>> >>>> >>>> > Hi Vishal, >>>> >>>> >>>> > >>>> >>>> >>>> > Can you show us how it be done with fork? >>>> >>>> >>>> > >>>> >>>> >>>> > On Fri, Jun 3, 2011 at 12:02 PM, Vishal Thanki >>>> >>>> >>>> > <[email protected]> >>>> >>>> >>>> > wrote: >>>> >>>> >>>> >> >>>> >>>> >>>> >> can use fork() also.. >>>> >>>> >>>> >> >>>> >>>> >>>> >> On Fri, Jun 3, 2011 at 11:57 AM, anand karthik >>>> >>>> >>>> >> <[email protected]> wrote: >>>> >>>> >>>> >> > (!printf("Hello")) >>>> >>>> >>>> >> > >>>> >>>> >>>> >> > On Jun 3, 2011 11:52 AM, "Arpit Mittal" >>>> >>>> >>>> >> > <[email protected]> >>>> >>>> >>>> >> > wrote: >>>> >>>> >>>> >> >> Please help me in this question. >>>> >>>> >>>> >> >> >>>> >>>> >>>> >> >> What's the "condition" so that the following code prints >>>> both >>>> >>>> >>>> >> >> HelloWorld ! >>>> >>>> >>>> >> >> >>>> >>>> >>>> >> >> if "condition" >>>> >>>> >>>> >> >> printf ("Hello"); >>>> >>>> >>>> >> >> else >>>> >>>> >>>> >> >> printf("World"); >>>> >>>> >>>> >> >> >>>> >>>> >>>> >> >> >>>> >>>> >>>> >> >> >>>> >>>> >>>> >> >> >>>> >>>> >>>> >> >> -- >>>> >>>> >>>> >> >> -Arpit Mittal >>>> >>>> >>>> >> >> 6th Semester, >>>> >>>> >>>> >> >> Indian Institute of Information Technology,Allahabad >>>> >>>> >>>> >> >> Email : [email protected] >>>> >>>> >>>> >> >> [email protected] >>>> >>>> >>>> >> >> Contact : +91-8853049787 >>>> >>>> >>>> >> >> >>>> >>>> >>>> >> >> Let every man be respected as an individual and no man >>>> >>>> >>>> >> >> idolized. >>>> >>>> >>>> >> >> >>>> >>>> >>>> >> >> -- >>>> >>>> >>>> >> >> You received this message because you are subscribed to >>>> the >>>> >>>> >>>> >> >> Google >>>> >>>> >>>> >> >> Groups >>>> >>>> >>>> >> >> "Algorithm Geeks" group. >>>> >>>> >>>> >> >> To post to this group, send email to >>>> >>>> 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http://groups.google.com/group/algogeeks?hl=en. >>>> >>>> >>>> > >>>> >>>> >>>> >>>> >>>> >>>> -- >>>> >>>> >>>> You received this message because you are subscribed to the >>>> Google >>>> >>>> >>>> Groups "Algorithm Geeks" group. >>>> >>>> >>>> To post to this group, send email to >>>> [email protected]. >>>> >>>> >>>> To unsubscribe from this group, send email to >>>> >>>> >>>> [email protected]. >>>> >>>> >>>> For more options, visit this group at >>>> >>>> >>>> http://groups.google.com/group/algogeeks?hl=en. >>>> >>>> >>>> >>>> >>>> >>> >>>> >>>> >>> >>>> >>>> >>> >>>> >>>> >>> -- >>>> >>>> >>> Cheers >>>> >>>> >>> Naveen Kumar >>>> >>>> >>> >>>> >>>> >>> -- >>>> >>>> >>> You received this message because you are subscribed to the >>>> Google >>>> >>>> >>> Groups >>>> >>>> >>> "Algorithm Geeks" group. >>>> >>>> >>> To post to this group, send email to >>>> [email protected]. >>>> >>>> >>> To unsubscribe from this group, send email to >>>> >>>> >>> [email protected]. >>>> >>>> >>> For more options, visit this group at >>>> >>>> >>> http://groups.google.com/group/algogeeks?hl=en. >>>> >>>> >> >>>> >>>> >> >>>> >>>> >> >>>> >>>> >> -- >>>> >>>> >> Regards, >>>> >>>> >> Shachindra A C >>>> >>>> >> >>>> >>>> >> -- >>>> >>>> >> You received this message because you are subscribed to the >>>> Google >>>> >>>> >> Groups >>>> >>>> >> "Algorithm Geeks" group. >>>> >>>> >> To post to this group, send email to [email protected] >>>> . >>>> >>>> >> To unsubscribe from this group, send email to >>>> >>>> >> [email protected]. >>>> >>>> >> For more options, visit this group at >>>> >>>> >> http://groups.google.com/group/algogeeks?hl=en. >>>> >>>> > >>>> >>>> > >>>> >>>> > >>>> >>>> > -- >>>> >>>> > With regards, >>>> >>>> > Vιиodh >>>> >>>> > >>>> >>>> > -- >>>> >>>> > You received this message because you are subscribed to the >>>> Google >>>> >>>> > Groups >>>> >>>> > "Algorithm Geeks" group. >>>> >>>> > To post to this group, send email to [email protected]. >>>> >>>> > To unsubscribe from this group, send email to >>>> >>>> > [email protected]. >>>> >>>> > For more options, visit this group at >>>> >>>> > http://groups.google.com/group/algogeeks?hl=en. >>>> >>>> > >>>> >>>> >>>> >>>> -- >>>> >>>> You received this message because you are subscribed to the Google >>>> >>>> Groups "Algorithm Geeks" group. >>>> >>>> To post to this group, send email to [email protected]. >>>> >>>> To unsubscribe from this group, send email to >>>> >>>> [email protected]. >>>> >>>> For more options, visit this group at >>>> >>>> http://groups.google.com/group/algogeeks?hl=en. >>>> >>>> >>>> >>> >>>> >>> >>>> >>> >>>> >>> -- >>>> >>> Cheers >>>> >>> Naveen Kumar >>>> >>> >>>> >>> -- >>>> >>> You received this message because you are subscribed to the Google >>>> Groups >>>> >>> "Algorithm Geeks" group. >>>> >>> To post to this group, send email to [email protected]. >>>> >>> To unsubscribe from this group, send email to >>>> >>> [email protected]. >>>> >>> For more options, visit this group at >>>> >>> http://groups.google.com/group/algogeeks?hl=en. >>>> >> >>>> >> -- >>>> >> You received this message because you are subscribed to the Google >>>> Groups >>>> >> "Algorithm Geeks" group. >>>> >> To post to this group, send email to [email protected]. >>>> >> To unsubscribe from this group, send email to >>>> >> [email protected]. >>>> >> For more options, visit this group at >>>> >> http://groups.google.com/group/algogeeks?hl=en. >>>> > >>>> > >>>> > >>>> > -- >>>> > Regards, >>>> > Nitish Goyal >>>> > Undergraduate Student Of NSIT, >>>> > Computer Engineering (B.E.) >>>> > Asst. PlaceComm 2011 >>>> > contact me:- +91-9999605824 >>>> > Reply at :- [email protected] >>>> > >>>> > -- >>>> > You received this message because you are subscribed to the Google >>>> Groups >>>> > "Algorithm Geeks" group. >>>> > To post to this group, send email to [email protected]. >>>> > To unsubscribe from this group, send email to >>>> > [email protected]. >>>> > For more options, visit this group at >>>> > http://groups.google.com/group/algogeeks?hl=en. >>>> > >>>> >>>> >>>> >>>> -- >>>> Lalit Kishore Sharma, >>>> IIIT Allahabad (Amethi Capmus), >>>> 6th Sem. >>>> >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "Algorithm Geeks" group. >>>> To post to this group, send email to [email protected]. >>>> To unsubscribe from this group, send email to >>>> [email protected]. >>>> For more options, visit this group at >>>> http://groups.google.com/group/algogeeks?hl=en. >>>> >>>> >>> >>> >>> -- >>> Regards, >>> Nitish Goyal >>> Undergraduate Student Of NSIT, >>> Computer Engineering (B.E.) >>> Asst. PlaceComm 2011 >>> contact me:- +91-9999605824 >>> Reply at :- [email protected] >>> >>> >>> -- >>> You received this message because you are subscribed to the Google Groups >>> "Algorithm Geeks" group. >>> To post to this group, send email to [email protected]. >>> To unsubscribe from this group, send email to >>> [email protected]. >>> For more options, visit this group at >>> http://groups.google.com/group/algogeeks?hl=en. >>> >> >> >> >> -- >> Cheers >> Naveen Kumar >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Algorithm Geeks" group. >> To post to this group, send email to [email protected]. >> To unsubscribe from this group, send email to >> [email protected]. >> For more options, visit this group at >> http://groups.google.com/group/algogeeks?hl=en. >> > > -- > You received this message because you are subscribed to the Google Groups > "Algorithm Geeks" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/algogeeks?hl=en. > -- Cheers Naveen Kumar -- You received this message because you are subscribed to the Google Groups "Algorithm Geeks" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/algogeeks?hl=en.
