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 information on this structure, see the
Handling the _IO_READ 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_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 resmgr_io_funcs_t table passed as the io_funcs argument 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 verify if this read operation should be permitted. If so, iofunc_read_default() indicates that it read zero bytes.
Returns:
- EOK
- This read operation was permitted.
- ENOSYS
- The extended type of the _IO_READ message is invalid.
This function can also return any error returned by iofunc_read_verify().
Classification:
| Safety: | |
|---|---|
| Cancellation point | No |
| Signal handler | Yes |
| Thread | Yes |