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cunixfork

fork() start of execution

I am pretty new to unix programming and came across something I do not understand. Here it is the following code snippet:

#include <stdio.h>
#include <sys/types.h>

int main()
{
     printf("%d ", fork());
     return 0;
}

The output is: 9298 0. Why does the child process call this printf ? At my course I was told that it executes everything after the fork() call. What am I getting wrong ?

Solution

  • The result of fork is passed to printf so it is executed before printf. Your code is equivalent to:

    #include <stdio.h>
#include <sys/types.h>

int main()
{
     pid_t pid = fork();
     printf("%d ", pid);
     return 0;
}