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close(2) [bsd man page]

CLOSE(2)							System Calls Manual							  CLOSE(2)

NAME
close - delete a descriptor SYNOPSIS
close(d) 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 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 further 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 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, 1)'' is provided, which arranges that a descriptor will be closed after a successful execve; the call ``fcntl(d, F_SETFD, 0)'' restores the default, which is to not close the 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. ERRORS
Close will fail if: [EBADF] D is not an active descriptor. SEE ALSO
accept(2), flock(2), open(2), pipe(2), socket(2), socketpair(2), execve(2), fcntl(2) 4th Berkeley Distribution May 22, 1986 CLOSE(2)

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CLOSE(2)						      BSD 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, the object 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 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 further flock(2)). When a process exits, all associated file descriptors are freed, but since there is a limit on active descriptors per processes, the close() function call is useful when a large quantity of file descriptors are being handled. 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(d, F_SETFD, 1)'' is provided, which arranges that a descriptor will be closed after a successful execve; the call ``fcntl(d, F_SETFD, 0)'' restores the default, which is to not close the descriptor. 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. ERRORS
Close() will fail if: [EBADF] D is not an active descriptor. [EINTR] An interrupt was received. SEE ALSO
accept(2), flock(2), open(2), pipe(2), socket(2), socketpair(2), execve(2), fcntl(2) STANDARDS
Close() conforms to IEEE Std 1003.1-1988 (``POSIX.1''). 4th Berkeley Distribution April 19, 1994 4th Berkeley Distribution

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