iofunc_close

Free all locks allocated for the client process

Synopsis:

#include <sys/iofunc.h>

int iofunc_close_dup( resmgr_context_t* ctp,
                      io_close_t* msg,
                      iofunc_ocb_t* ocb,
                      iofunc_attr_t* attr );

Arguments:

ctp: A pointer to a resmgr_context_t structure that the resource-manager library uses to pass context information between functions.
msg: A pointer to the io_close_t structure that contains the message that the resource manager received; see below.
ocb: A pointer to the iofunc_ocb_t structure for the Open Control Block that was created when the client opened the resource.
attr: A pointer to the iofunc_attr_t structure that describes the characteristics of the device that's associated with your resource manager.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The iofunc_close_dup() helper function handles a _IO_CLOSE message. This function frees all locks allocated for the client process on the file descriptor and performs any POSIX-related cleanup required when a duplicated ocb is detached.

io_close_t structure

The io_close_t structure holds the _IO_CLOSE message received by the resource manager:

struct _io_close {
    uint16_t                    type;
    uint16_t                    combine_len;
};

typedef union {
    struct _io_close            i;
} io_close_t;

The I/O message structures are unions of an input message (coming to the resource manager) and an output or reply message (going back to the client). In this case, there's only an input message, i.

The i member is a structure of type _io_close that contains the following members:

type: _IO_CLOSE.
combine_len: If the message is a combine message, _IO_COMBINE_FLAG is set in this member. For more information, see the Combine Messages chapter of Writing a Resource Manager.

CAUTION:

This handler function is executed without locking. To avoid race conditions in multi-threaded server processes, you must serialize access to the iofunc_attr_t structure in the attr argument. For more information, see the note about locking attribute structures in “Unblocking if someone closes a file descriptor” in Writing a Resource Manager.

Returns:

EOK: Success.
Anything else: An error occurred.

Classification:

QNX Neutrino

Safety:
Cancellation point	No
Interrupt handler	No
Signal handler	Yes
Thread	Yes