CallTimeout

Sends a message to a port and blocks until the server replies, or until a timeout.

Number	Selector	Blocking	Since
0x05 SVC_CALL	—	yes	2.0

SvcResult CallTimeout(Handle port, uint32_t xlen, Handle grant_handle, Duration timeout);

Registers: (port, xlen, grant, timeout) -> r0 status, r1 reply length, r3 granted handle

The request is the first xlen bytes of the caller's message box; the reply arrives in the same place. Callers queue by priority, and the server runs at the caller's priority while serving (priority inheritance).

The timeout covers the whole call: waiting to be received and waiting for the reply. When it expires the call is withdrawn. A server that already took it finds its reply capability gone: a late Reply() returns ERR_BADHANDLE, and a late ReplyRecv() just waits for the next call, so the stale answer cannot be mistaken for the reply to a later call.

Parameters

Name	Direction	Description
port	in	Port handle with PERM_SEND.
xlen	in	Request length in bytes, at most MSG_BUF_SIZE.
grant_handle	in	Handle (with PERM_TXFR) to copy to the server, or -1.
timeout	in	Milliseconds to wait for the reply, or TIMEOUT_INFINITE. TIMEOUT_POLL always returns ERR_TIMEOUT, since a call cannot finish without blocking.

Returns

r0 is the status; r1 the reply length; r3 a handle granted back, or -1.

Errors

Error	Condition
ERR_TIMEOUT	No reply within timeout.
ERR_OVERFLOW	xlen is larger than MSG_BUF_SIZE.
ERR_BADHANDLE	port or grant_handle is not a live handle.
ERR_BADTYPE	port is not a port.
ERR_NOPERM	port lacks PERM_SEND, or grant_handle lacks PERM_TXFR.
ERR_DEAD	The port died, or the server died before replying.
ERR_NOMEM	The server's handle table is full (when granting).