@nitish I think using fork() it is not possible , to achieve , what you are trying to do .. Because , though address space is shared , but all the variable of parent process can't be communicated through child process.as they dont have a shared memory block.where we can place our semaphore.
It would be better if you use , a global variable and 2 threads and try to show how semaphores work. Correct Me , if I am wrong ..!! On Fri, Jun 3, 2011 at 11:26 PM, nicks <[email protected]> wrote: > @naveen.. thanks...i got it finally :) > > On Fri, Jun 3, 2011 at 10:35 AM, Naveen Kumar <[email protected]> > wrote: >> >> 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 >>>>>> >>>> >>>> >> >> [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. >>>>>> >>>> >>>> >> > >>>>>> >>>> >>>> >> >>>>>> >>>> >>>> >> -- >>>>>> >>>> >>>> >> 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. >>>>>> >>>> >> >>>>>> >>>> >> >>>>>> >>>> >> >>>>>> >>>> >> -- >>>>>> >>>> >> 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. > > -- > 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.
