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close(2) [ultrix man page]

close(2)							System Calls Manual							  close(2)

Name
       close - delete a descriptor

Syntax
       close(fd)
       int fd;

Description
       The  call  deletes  a  descriptor  from	the per-process object reference table.  If the descriptor is the last reference to the underlying
       object, then the object is deactivated.	For example, on the last close of a file, the current pointer associated with the  file  is  lost.
       On  the	last  close  of a socket, discards associated naming information and queued data.  On the last close of a file holding an advisory
       lock, the lock is released.  For further information, see

       A process's descriptors are automatically closed when a process exits, but because each	process  can  have  a  limited	number	of  active
       descriptors, is necessary for programs that deal with many descriptors.

       When  a	process  forks,  all descriptors for the new child process reference the same objects as they did in the parent process before the
       fork.  For further information, see If a new process is then to be run using the process would normally inherit these descriptors.  Most of
       the  descriptors  can  be  rearranged  with the system call or deleted with before is called. However, if any descriptors are needed if the
       fails, they must be closed if the execve succeeds.  For this reason, the call, fcntl(d, F_SETFD, 1), is provided. This call arranges that a
       descriptor is closed after a successful call.  The call, fcntl(d, F_SETFD, 0), restores the default, which is to not close the descriptor.

       When  is  used  on  a  descriptor  that	refers to a remote file over NFS, and that file has been modified by using then any cached data is
       flushed before returns. If an asynchronous write error has occurred previously with this remote file, or occurred  as  part  of	the  flush
       operation described above, then returns -1 and errno will be set to the error code. The return code from should be inspected by any program
       that can over NFS.

Return Values
       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.

Diagnostics
       The system call fails under the following conditions:

       [EBADF]	      D is not an active descriptor.

       [EINTR]	      The function was interrupted by a signal.

       If  an  error occurs on an asynchronous write over NFS, the error cannot always be returned from a system call.	The error code is returned
       on or The following are NFS-only error messages:

       [EACCESS]      The requested address is protected, and the current user has inadequate permission to access it.

       [ENOSPC]       There is no free space remaining on the file system containing the file.

       [EDQUOT]       The user's quota of disk blocks on the file system containing the file has been exhausted.

       [EIO]	      An I/O error occurred while reading from or writing to the file system.

       [EROFS]	      The file is on a read-only file system.

       [ESTALE]       The fd argument is invalid because the file referred to by that file handle no longer exists or has been revoked.

       [ETIMEDOUT]    A write operation failed because the server did not properly respond after a  period  of	time  that  is	dependent  on  the
		      options.

See Also
       accept(2), execve(2), fcntl(2), flock(2), fsync(2), open(2), pipe(2), socket(2), socketpair(2), write(2)

																	  close(2)

Check Out this Related Man Page

CLOSE(2)							System Calls Manual							  CLOSE(2)

NAME
close - delete a descriptor SYNOPSIS
#include <unistd.h> int close(int d) DESCRIPTION
The close call deletes a descriptor 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 seek pointer associated with the file is lost; on the last close of a TCP/IP descriptor associated naming information and queued data are discarded; on the last close of a file holding an advi- sory lock the lock is released (see further fcntl(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 that 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 descrip- tors 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(d, F_SETFD, flags)'' is provided, that can be used to mark a descriptor "close on exec" by setting the FD_CLOEXEC flag: fcntl(d, F_SETFD, fcntl(d, F_GETFD) | FD_CLOEXEC); 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. ERRORS
Close will fail if: [EBADF] D is not an active descriptor. SEE ALSO
open(2), pipe(2), execve(2), fcntl(2). 4th Berkeley Distribution May 22, 1986 CLOSE(2)

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