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close(2) [opendarwin man page]

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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CLOSE(2)						      BSD System Calls Manual							  CLOSE(2)

NAME
close -- delete a descriptor LIBRARY
Standard C Library (libc, -lc) SYNOPSIS
#include <unistd.h> int close(int d); DESCRIPTION
The close() system 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 flock(2)). When a process exits, all associated descriptors are freed, but since there is a limit on active descriptors per processes, the close() sys- tem call is useful when a large quantity of file descriptors are being handled. When a process calls 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 only if the execve() succeeds. For this reason, the system call fcntl(d, F_SETFD, 1); is provided, which arranges that a descriptor ``d'' will be closed after a successful execve(); the system call fcntl(d, F_SETFD, 0); restores the default, which is to not close descriptor ``d''. RETURN VALUES
Upon successful completion, a value of 0 is returned. Otherwise, a value of -1 is returned and 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), execve(2), fcntl(2), flock(2), open(2), pipe(2), socket(2), socketpair(2) STANDARDS
The close() function conforms to ISO/IEC 9945-1:1990 (``POSIX.1''). BSD
April 19, 1994 BSD

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