iofunc_read_default()

Default handler for _IO_READ messages

Synopsis:

#include <sys/iofunc.h>

int iofunc_read_default( resmgr_context_t *ctp,
                         io_read_t *msg,
                         iofunc_ocb_t *ocb );

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_read_t structure that contains the message that the resource manager received. For more information, see the documentation for iofunc_read_verify().

ocb

A pointer to the iofunc_ocb_t structure for the Open Control Block that was created when the client opened the resource.

Library:

libc

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

Description:

The iofunc_read_default() function implements POSIX semantics for the client's read() call, which is received as an _IO_READ message by the resource manager.

You can place this function directly into the io_funcs table passed to resmgr_attach(), at the read position, or you can call iofunc_func_init() to initialize all of the functions to their default values.

The iofunc_read_default() function calls iofunc_read_verify() to check the permissions on the file. If the permissions are appropriate, iofunc_read_default() indicates that it read zero bytes.

Returns:

EBADF

The client doesn't have read access to this resource.

EINVAL

The extended type information is invalid.

EOK

The client has read access to this resource.

Classification:

QNX Neutrino

See also:

iofunc_func_init(), iofunc_ocb_t, iofunc_read_verify(), resmgr_attach(), resmgr_context_t, resmgr_io_funcs_t

Writing a Resource Manager

Resource Managers chapter of Getting Started with QNX Neutrino