Exchange/SNA Manual

READ Procedure
Exchange/SNA System Procedure Calls
5–16 104700 Tandem Computers Incorporated
READ Procedure The READ procedure reads a record sent by the host to the specified subdevice.
CALL READ ( filenum
, buffer
, read-count
, [ count-read ]
, [ tag ] );
filenum
INT:value
is the file number of a previously opened subdevice supported by the
Exchange/SNA line server. The number you specify here is the number returned
by the call to OPEN that opened the subdevice.
buffer
INT:ref:*
is an array in which the record read from the subdevice is returned. The array
should be as large or larger than the largest record you expect to receive from the
host.
read-count
INT:value
is the maximum number of bytes your program expects to read. This number
should be as large or larger than the size of the largest record you expect to receive
from the host. The maximum record size that the line server can receive is 255
bytes. If the record is larger than read-count bytes, the record is truncated to
read-count bytes. read-count must be no larger than the size of buffer .
count-read
INT:ref:1
returns the number of bytes in the record read from the subdevice. This parameter
is used for wait I/O only. For nowait I/O, you can omit this parameter; the
number of bytes read is returned in the count-transferred parameter of the
AWAITIO procedure that completes the read operation.