ralph@cs.ubc.ca (Scott Ralph) (11/09/90)
I am having trouble using nrecv() when the data field
becomes larger than 4096 bytes -- the maximum number of
bytes for a single message.
extern int errno;
struct nmsg header;
HostMessage host_message;
typedef Message *MessagePtr;
typedef struct hMsg {
unsigned char sending_processor;
unsigned char rows;
unsigned char cols;
unsigned char type;
unsigned char generation;
char data [NUMBER_PIXELS_IN_REGION];
} HostMessage;
typedef HostMessage *HostMessagePtr;
header.nh_event = 0;
header.nh_type = 0;
header.nh_length = sizeof (HostMessage);
header.nh_flags = 0;
header.nh_msg = (char *) &host_message;
if ( nrecv (&header)) {
printf("Death # 1 -- %d\n", errno);
fflush(stdout);
kexit (errno);*
}
The nrecv() returns with errno #4 -- EINTR
This corresponds to an interrupted system call.
NSEND(l) TROLLIUS NETWORK LIBRARY NSEND(l)
The nh_length field holds the length (in bytes) of the mes-
sage to be sent. If the sender and the receiver specify
different lengths, the lesser amount will be transferred.
The datalink functions called by nsend have a maximum mes-
sage length of MAXNMSGLEN (defined in <trillium/net.h> and
currently set to 4096 bytes). Messages exceeding this
length will be implicitly broken down into a series of
smaller messages, which will be recombined at the receiving
end.
-------------
I am not sure if additional information must be specified (i.e.
the nh_flags field?) or not.
Any Suggestions?
-- scott ralph