iofunc_pathconf()

Support pathconf() requests

Synopsis:

#include <sys/iofunc.h>

int iofunc_pathconf( resmgr_context_t *ctp,
                     io_pathconf_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_pathconf_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_pathconf() helper function does what's needed to support pathconf() with the mount and attr passed to it. Other fsys pathconf() requests need to be handled by the caller.

If you write your own pathconf callout for your resource manager, use the following macro to pass the requested value back to the caller:

_IO_SET_PATHCONF_VALUE( resmgr_context_t *ctp,
                        int value )

io_pathconf_t structure

The io_pathconf_t structure holds the _IO_PATHCONF message received by the resource manager:

struct _io_pathconf {
    uint16_t                    type;
    uint16x_t                    combine_len;
    short                       name;
    uint16_t                    zero;
};

typedef union {
    struct _io_pathconf         i;
/*  value is returned with MsgReply */
} io_pathconf_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_pathconf that contains the following members:

type

_IO_PATHCONF.

combine_len

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

name

The name of the configurable limit; see pathconf().

Returns:

EOK, or _RESMGR_DEFAULT if the function didn't handle the pathconf() request.

Classification:

QNX Neutrino

See also:

iofunc_attr_t, iofunc_ocb_t, iofunc_pathconf_default(), pathconf(), resmgr_context_t

Writing a Resource Manager

Resource Managers chapter of Getting Started with QNX Neutrino