FORK(2)                 COMMAND REFERENCE                 FORK(2)



NAME
     fork - create a new process

SYNOPSIS
     pid = fork()
     int pid;

DESCRIPTION
     Fork causes creation of a new process.  The new process
     (child process) is an exact copy of the calling process
     (parent process) except for the following:

          The child process has a unique process ID.

          The child process has a different parent process ID
          (i.e., the process ID of the parent process).

          The child process has its own copy of the parent's
          descriptors.  These descriptors reference the same
          underlying objects, so that, for instance, file
          pointers in file objects are shared between the child
          and the parent, so that a lseek(2) on a descriptor in
          the child process can affect a subsequent read or write
          by the parent.  This descriptor copying is also used by
          the shell to establish standard input and output for
          newly created processes as well as to set up pipes.

          The child processes resource utilizations are set to 0;
          see setrlimit(2).

DIAGNOSTICS
     Fork will fail and no child process will be created if one
     or more of the following are true:

     [EAGAIN]
         The system-imposed limit on the total number of
         processes under execution, NPROC, would be exceeded.

     [EAGAIN]
         The system-imposed limit on the total number of
         processes under execution by a single user, MAXUPRC,
         defined in <sys/param.h>, would be exceeded.

     [ENOMEM]
         Insufficient space exists in the swap area for the child
         process.

RETURN VALUE
     Upon successful completion, fork returns a value of 0 in pid
     to the child process and returns the process ID of the child
     process in pid to the parent process.  Otherwise, a value of
     -1 is returned to the parent process, no child process is



Printed 10/17/86                                                1

FORK(2)                 COMMAND REFERENCE                 FORK(2)



     created, and the global variable errno is set to indicate
     the error.

SEE ALSO
     execve(2), setrlimit(2), vfork(2), wait(2).


















































Printed 10/17/86                                                2

%%index%%
na:72,63;
sy:135,192;
de:327,1153;
di:1480,628;
rv:2108,376;2628,90;
se:2718,203;
%%index%%000000000115