fcntl64 - manipulate file descriptor

NAME LIBRARY SYNOPSIS DESCRIPTION Duplicating a file descriptor File descriptor flags File status flags Advisory record locking Open file description locks (non-POSIX) Managing signals Leases File and directory change notification (dnotify) Changing the capacity of a pipe File Sealing File read/write hints RETURN VALUE ERRORS VERSIONS STANDARDS HISTORY SEE ALSO

SYNOPSIS

#include <fcntl.h>

int fcntl(int fd, int op, ...);

DESCRIPTION

fcntl() performs one of the operations described below on the open file descriptor fd. The operation is determined by op.

Certain of the operations below are supported only since a particular Linux kernel version. The preferred method of checking whether the host kernel supports a particular operation is to invoke fcntl() with the desired op value and then test whether the call failed with EINVAL, indicating that the kernel does not recognize this value.

Duplicating a file descriptor

F_DUPFD(2const)
F_DUPFD_CLOEXEC(2const)

File descriptor flags

F_GETFD(2const)
F_SETFD(2const)

File status flags

F_GETFL(2const)
F_SETFL(2const)

Advisory record locking

F_SETLK(2const)
F_SETLKW(2const)
F_GETLK(2const)

Open file description locks (non-POSIX)

F_OFD_SETLK(2const)
F_OFD_SETLKW(2const)
F_OFD_GETLK(2const)

Managing signals

F_GETOWN(2const)
F_SETOWN(2const)
F_GETOWN_EX(2const)
F_SETOWN_EX(2const)
F_GETSIG(2const)
F_SETSIG(2const)

Leases

F_SETLEASE(2const)
F_GETLEASE(2const)

File and directory change notification (dnotify)

F_NOTIFY(2const)

Changing the capacity of a pipe

F_SETPIPE_SZ(2const)
F_GETPIPE_SZ(2const)

File Sealing

F_ADD_SEALS(2const)
F_GET_SEALS(2const)

File read/write hints

F_GET_RW_HINT(2const)
F_SET_RW_HINT(2const)
F_GET_FILE_RW_HINT(2const)
F_SET_FILE_RW_HINT(2const)

RETURN VALUE

For a successful call, the return value depends on the operation.

On error, −1 is returned, and errno is set to indicate the error.

ERRORS

EACCES or EAGAIN

Operation is prohibited by locks held by other processes.

	EAGAIN		The operation is prohibited because the file has been memory-mapped by another process.
	EBADF		fd is not an open file descriptor
	EINVAL		The value specified in op is not recognized by this kernel.