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about fork()

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mlfever
mlfever Posts: 1
in Kernel Development

i am learning the kernel,the fork() ,i have some questions,and read some from the net,but not very know about it

the source:

#include

#include

#include

void main()

{

int i;

int p_id;

printf("aaa");

p_id=fork();

if(p_id==0)

{

for(i=1;i<3;i++)<br />
{ printf("this is child process\n"); }

}

if(p_id==-1)

{

printf("fork new process error!\n");

}

if(p_id==0)

{

printf("iii");

for(i=1;i<3;i++)<br />
{ printf("this is parent process\n" ); }

}

printf("bbb");

}

yanj@yanj-desktop:~/lianxi/chapter2$ ./forktest

aaathis is child process

this is child process

iiithis is parent process

this is parent process

I know fork() copy the two same program to child,parent process,

why can show "aaa",cannot "bbb"

Comments

  • shelner
    shelner Posts: 19
    Options
    I dunno help you with your problem but learn to use the BB codes. The code you put into bb code, then it would be readable, dude.
  • woboyle
    woboyle Posts: 501
    Options
    You have two blocks that are testing for a child process and none that check for parent process. Try this: 
    if(p_id==0)
{
    for(i=1;i<3;i++)
        { printf("this is child process\\n"); }
}
else if(p_id==-1)
{
    printf("fork new process error!\\n")
}
else
{
    for(i=1;i<3;i++)
        { printf("this is parent process\\n" ); }
}

    Cute! The code processor strips out the backslashes in the code example! Let's try doubling them to see if they display correctly...
    Ok, that works. Note to forum moderator(s) - the code block processor is incorrectly stripping out new-line (backslash-n) in C code. Not good.

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