blob: e53c3431cd085534a8aea5eed181de66d813b10f (
plain) (
tree)
|
|
The requests can be of two types :
- Blocking, IE the sender waits for an answer
- Nonblocking, the request is a simple message.
Requests are identified by a 32bit function number, composed as follows :
(8 bit) parameter and return type ; (24bit) function number
the first 8 bits are :
2bit answer type ; 2bit parameter a type ; 2bit parameter b type ; 2bit parameter c type
each two bit couple can be one of the following :
- 00 : void
- 01 : object descriptor number (will be copied with a new number to reciever)
- 10 : long
- 11 : long long (replies), or shared memory offset in sender's space (requests and messages)
When shared memory segments are sent as request parameters from a process to the same process, the pointer
to the memory is kept and sent to the handler function. If handler is in another process, receiver will
have to call request_mapShm specifying a pointer. Shared memory is automatically unmapped when requests
yields an answer, and is kept when the request is nonblocking (message).
When objects are sent as request parameters, the receiver process will get an immediately usable object
descriptor. The descriptor is closed in blocking requests after the request yields an answer (except if the
request is handled in the same process than the sender, OR if the receiver already had a descriptor to
this object). The descriptor is kept when sent by a nonblocking request (message).
|
