Name

fcntl

fcntl fileId attribute [value]

Modify or return the current value of a file option associated with an open file identifier. If only attribute is specified, its current value is returned. If a boolean value is specified, the attribute is set. Some values are read only. The following attributes may be specified:

RDONLY

File is opened for reading (read only).

WRONLY

File is opened for writing (read only).

RDWR

File is opened for reading and writing (read only).

READ

File is readable (read only).

WRITE

File is writable (read only).

APPEND

File is opened for appending.

NONBLOCK

File uses nonblocking I/O.

CLOEXEC

Close the file upon execution of a new process.

NOBUF

File is not buffered.

LINEBUF

File is line buffered.

KEEPALIVE

Keep-alive option is enabled for a socket.

The APPEND and CLOEXEC attributes are not available on Windows.

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