CLOSE(2)                COMMAND REFERENCE                CLOSE(2)



NAME
     close - delete a descriptor

SYNOPSIS
     close(fd)
     int fd;

DESCRIPTION
     The close call deletes the descriptor fd from the per-
     process object reference table.  If this is the last
     reference to the underlying object, then it will be
     deactivated.  For example, on the last close of a file the
     current lseek pointer associated with the file is lost; on
     the last close of a socket(2) associated naming information
     and queued data are discarded; on the last close of a file
     holding an advisory lock the lock is released (see
     flock(2)).

     A close of all of a process's descriptors is automatic on
     exit, but since there is a limit on the number of active
     descriptors per process, close is necessary for programs
     which deal with many descriptors.

     When a process forks (see fork(2)), all descriptors for the
     new child process reference the same objects as they did in
     the parent before the fork.  If a new process is then to be
     run using execve(2), the process would normally inherit
     these descriptors.  Most of the descriptors can be
     rearranged with dup2(2) or deleted with close before the
     execve is attempted, but if some of these descriptors will
     still be needed if the execve fails, it is necessary to
     arrange for them to be closed if the execve succeeds.  For
     this reason, the call ``fcntl(fd, F_SETFD, 1)'' is provided
     which arranges that a descriptor will be closed after a
     successful execve; the call ``fcntl(fd, F_SETFD, 0)''
     restores the default, which is to not close the descriptor.

DIAGNOSTICS
     Close will fail if:

     [EBADF]
         Fd is not an active descriptor.

RETURN VALUE
     Upon successful completion, a value of 0 is returned.
     Otherwise, a value of -1 is returned and the global integer
     variable errno is set to indicate the error.

SEE ALSO
     accept(2), close(2), dup(2), execve(2), fcntl(2), flock(2),
     fork(2), open(2), pipe(2), socket(2), socketpair(2).




Printed 10/17/86                                                1

%%index%%
na:72,63;
sy:135,176;
de:311,1798;
di:2109,193;
rv:2302,264;
se:2566,313;
%%index%%000000000107