fork (3f)

creates a copy of a calling process

Syntax

  integer*4 fork, irtn
  external fork
  irtn = fork( )

Description

  The fork function creates a copy of the calling process.  The only
  distinction between the two processes is that the value returned to the
  calling (parent) process is the process ID of the copy (child).  The value
  returned to the child process is 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 files.

  A corresponding exec routine is not provided because there is no
  satisfactory way to retain open logical units across the exec.  See
  system(3f) to perform the usual function of fork/exec.

Return Values

  If the function returns a negative value, it indicates an error and is the
  negation of the system error code.  (See perror(3f).)

See Also

  kill(3f), perror(3f), system(3f), wait(3f)