iofunc_write_default()

Updated: October 26, 2022

Default handler for _IO_WRITE messages

Synopsis:

#include <sys/iofunc.h>

int iofunc_write_default( resmgr_context_t* ctp,
                          io_write_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_write_t structure that contains the message that the resource manager received. For information on this structure, see the Handling the _IO_WRITE message topic in the Writing a Resource Manager guide.
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_write_default() function implements POSIX semantics for the client's write() call, which is received as an _IO_WRITE message by the resource manager. It doesn't actually write the given data anywhere.

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

The iofunc_write_default() function calls iofunc_write_verify() to verify if this write operation should be permitted. If so, iofunc_write_default() indicates that it wrote the requested number of bytes.

Returns:

EOK
This write operation was permitted.
EBADF
The client doesn't have write access to this resource.
EINVAL
An unknown xtype was given.

Classification:

QNX Neutrino

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