получить UMAD (receive umad)
Имя (Name)
umad_recv - receive umad
Синопсис (Synopsis)
#include <infiniband/umad.h>
int umad_recv(int portid, void *umad, int *length, int timeout_ms);
Описание (Description)
umad_recv() waits up to timeout_ms milliseconds for an incoming
MAD message to be received from the port specified by portid.
A MAD "message" consists of a single MAD packet or a coalesced
multipacket RMPP transmission. In the RMPP case the header of
the first RMPP packet is returned as the header of the buffer and
the buffer data contains the coalesced data section of each
subsequent RMPP MAD packet within the transmission. Thus all the
RMPP headers except the first are not copied to user space from
the kernel.
The message is copied to the umad buffer if there is sufficient
room and the received length is indicated. If the buffer is not
large enough, the size of the umad buffer needed is returned in
length. A negative timeout_ms makes the function block until a
packet is received. A timeout_ms parameter of zero indicates a
non blocking read.
Note length is a pointer to the length of the data portion of the
umad buffer. This means that umad must point to a buffer at
least umad_size() + *length bytes long.
Note also that *length must be >= 256 bytes. This length allows
for at least a single MAD packet to be returned.
Возвращаемое значение (Return value)
umad_recv() on success return the agentid; on error, errno is set
and a negative value is returned as follows:
-EINVAL invalid port handle or agentid or *length is less
than the minimum supported
-EIO receive operation failed
-EWOULDBLOCK non blocking read can't be fulfilled
-ENOSPC The provided buffer is not long enough for the
complete message.
Смотри также (See also)
umad_poll(3)
