FORK
Section: Linux Programmer's Manual (2)
Updated: 10 June 1995
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NAME
fork, vfork - create a child process
SYNOPSIS
#include <unistd.h>
pid_t fork(void);
pid_t vfork(void);
DESCRIPTION
fork
creates a child process that differs from the parent process only in its
PID and PPID, and in the fact that resource utilizations are set to 0.
File locks and pending signals are not inherited.
Under Linux,
fork
is implemented using copy-on-write pages, so the only penalty incurred by
fork is the time and memory required to duplicate the parent's page tables,
and to create a unique task structure for the child.
RETURN VALUE
On success, the PID of the child process is returned in the parent's thread
of execution, and a 0 is returned in the child's thread of execution. On
failure, a -1 will be returned in the parent's context, no child process
will be created, and
errno
will be set appropriately.
ERRORS
- EAGAIN
-
fork
cannot allocate sufficient memory to copy the parent's page tables and
allocate a task structure for the child.
BUGS
Under Linux,
vfork
is merely an alias for
fork.
fork
does never return the error
ENOMEM.
CONFORMING TO
SVID, AT&T, POSIX, X/OPEN, BSD 4.3
SEE ALSO
clone(2), execve(2), wait(2)
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- ERRORS
-
- BUGS
-
- CONFORMING TO
-
- SEE ALSO
-
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