CLOSE Section: Linux Programmer's Manual (2) Updated: April 14, 2025 Index   NAME close - close a file descriptor   SYNOPSIS #include <unistd.h> int close(int fd);   DESCRIPTION close closes a file descriptor, so that it no longer refers to any file and may be reused. Any locks held on the file it was associated with, and owned by the process, are removed (regardless of the file descriptor that was used to obtain the lock). If fd is the last copy of a particular file descriptor the resources associated with it are freed; if the descriptor was the last reference to a file which has been removed using the file is deleted.   RETURN VALUE close returns zero on success, or -1 if an error occurred.   ERRORS EBADF fd isn't a valid open file descriptor.   CONFORMING TO SVr4, SVID, POSIX, X/OPEN, BSD 4.3. SVr4 documents an additional ENOLINK error condition.   NOTES Not checking the return value of close is a common but nevertheless serious programming error. File system implementations which use techniques as ``write-behind'' to increase performance may lead to succeeding, although the data has not been written yet. The error status may be reported at a later write operation, but it is guaranteed to be reported on closing the file. Not checking the return value when closing the file may lead to silent loss of data. This can especially be observed with NFS and disk quotas.   SEE ALSO   Index NAME SYNOPSIS DESCRIPTION RETURN VALUE ERRORS CONFORMING TO NOTES SEE ALSO This document was created by using the manual pages. Time: 11:56:05 GMT, March 24, 2025