bsd man page for fork

FORK(3F)																  FORK(3F)

NAME
       fork - create a copy of this process

SYNOPSIS
       integer function fork()

DESCRIPTION
       Fork  creates  a  copy  of  the	calling  process.   The only distinction between the 2 processes is that the value returned to one of them
       (referred to as the `parent' process) will be the process id of the copy.  The copy is usually referred to as  the  `child'  process.   The
       value returned to the `child' process will be zero.

       All logical units open for writing are flushed before the fork to avoid duplication of the contents of I/O buffers in the external file(s).

       If the returned value is negative, it indicates an error and will be the negation of the system error code.  See perror(3F).

       A corresponding exec routine has not been provided because there is no satisfactory way to retain open logical units across the exec.  How-
       ever, the usual function of fork/exec can be performed using system(3F).

FILES
       /usr/lib/libU77.a

SEE ALSO
       fork(2), wait(3F), kill(3F), system(3F), perror(3F)

4.2 Berkeley Distribution					   May 27, 1986 							  FORK(3F)