HP 3000 Manuals HP 3000 Manuals
READSTREAM
READSTREAMreads all or part of the untranslated host data stream.
Syntax
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| |
| I I I CA |
| READSTREAM (terminalid, offset,maxinbuflen, inbuf,|
| |
| I I |
| actinbuflen, result) |
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Parameters
terminalid (input)
Integer identifying the terminal. The terminalid is returned in a call
to the OPEN3270 intrinsic.
offset (input)
Integer indicating the offset, in characters, into the data stream. The
first character in the data stream has an offset of zero. The data
transfer begins at the location you specify in offset. The offset
parameter must be zero when the DBCS option to the OPEN3270 intrinsic is
enabled.
maxinbuflen (input)
Integer specifying the maximum number of characters to return in inbuf.
inbuf (output)
Character array containing the data stream.
actinbuflen (output)
Integer indicating the number of characters actually returned in inbuf.
result (output)
The following values can be generated by the READSTREAM intrinsic:
0 = Successful completion.
1 = Device not open.
9 = Host modified screen since the last receive
request. (MPE V only)
21 = Field offset specified is out of range.
22 = BASIC calling sequence error has occurred.
25 = Intrinsic call made while in split stack
mode.
26 = Intrinsic call made with the parameter value
out of bounds.
29 = Called intrinsic with a request already
outstanding. (No-wait I/O only)
30 = Internal error occurred in IMF intrinsic.
49 = Value specified for the INBUF parameter is too
small to hold the entire data stream.
50 = Called READSTREAM without calling RECV3270
first.
52 = Data stream is too long.
54 = Device not opened in transparent mode.
100 = A bad (non-zero) offset was specified in the
intrinsic call.
Description
To use the READSTREAM intrinsic, open a device in transparent mode by
calling the OPEN3270 intrinsic with bit 14 of the flags parameter set to
1.
With SDLC protocol, data received from the host is contained in the
Request Unit (RU). The RU is preceded by some header bytes known as the
Request Header (RH). The RU contains the data stream commands and the
data. Each LU.T2 and LU.T3 RU (or each RU chain, if RU chaining is used)
from the host contains a 3270 data stream command. LU.T1 RUs contain SCS
control codes instead of 3270 data stream commands.
SNA IMF removes the RH bytes and stores the rest of the RU in the
internal screen image. For LU.T2 and LU.T3 sessions, the first byte in
the internal screen image is the 3270 data stream write command.
To obtain host data, first call the RECV3270 intrinsic, and then call the
READSTREAM intrinsic. After calling RECV3270, the stream of data
received from the host is buffered in the internal screen image. Calling
READSTREAM retrieves the data from the internal screen image. You can
access all or any part of the RU through the READSTREAM intrinsic.
If the host attempts to write more data to your internal screen image
before you have called RECV3270 to retrieve the data already stored
there, SNA IMF rejects the command with sense code X'0820', "device
busy." This rejection prevents the host from writing over a data stream
that you have not received. You should call RECV3270 and READSTREAM for
every RU received.
The READSTREAM intrinsic can be called only in transparent mode. See
chapter 2 for more information about transparent mode.
COBOL Calling Sequence
CALL "CREADSTREAM" USING TERMINALID OFFSET MAXINBUFLEN INBUF ACTINBUFLEN
RESULT. (on MPE V and in compatibility mode on MPE XL)
CALL INTRINSIC "READSTREAM" USING TERMINALID OFFSET MAXINBUFLEN INBUF
ACTINBUFLEN RESULT. (in native mode on MPE XL)
All parameters are numeric data items except INBUF, which is an
alphanumeric data item.
FORTRAN Calling Sequence
CALL READSTREAM (TERMINALID, OFFSET, MAXINBUFLEN, INBUF, ACTINBUFLEN,
RESULT)
All parameters are integer variables except INBUF, which is a character
array.
BASIC Calling Sequence
CALL BREADSTREAM (T, O1, L7, I$, L8, R) (on MPE V and in compatibility
mode on MPE XL)
CALL READSTREAM (T, O1, L7, I$, L8, R) (in native mode on MPE XL)
All parameters are integer variables except I$, which is a string
variable.
NOTE Because BASIC cannot read a string of more than 255 characters, and
because the length of a screen will exceed 255 characters, you can
use the maxinbuflen parameter to prevent the BASIC string variable
from overflowing. offset allows you to choose the portion of the
screen to read. Multiple calls to READSTREAM with different offset
values can give BASIC programs the entire screen.
SPL Calling Sequence
READSTREAM (TERMINALID, OFFSET, MAXINBUFLEN, INBUF, ACTINBUFLEN, RESULT)
All parameters are integer data items except INBUF, which is a byte
array.
Pascal Calling Sequence
READSTREAM (TERMINALID, OFFSET, MAXINBUFLEN, INBUF, ACTINBUFLEN, RESULT);
All parameters are short integers except for INBUF, which is a packed
array of char.
C/XL Calling Sequence
READSTREAM (&TERMINALID, &OFFSET, &MAXINBUFLEN, INBUF, &ACTINBUFLEN,
&RESULT);
All parameters are of type short, except INBUF, which is a character
array (a pointer to a char).
Pascal Program Excerpts
Following are excerpts from a Pascal program that calls SNA IMF
intrinsics. For examples of complete Pascal programs in non-transparent
and transparent modes, see appendix F, "Sample Programs."
{************************** Global Declarations **************************}
type
shortint = -32768..32767; { global type, two bytes (half word) }
.
.
.
var
terminalid : shortint; { value returned by OPEN3270 intrinsic }
result : shortint;
.
.
.
procedure READSTREAM; intrinsic;
.
.
.
{************************** Local Declarations **************************}
var
offset : shortint; { All READSTREAM variables except }
maxinbuflen : shortint; { terminalid and result are local. }
inbuf : packed array[1..1920] of char;
actinbuflen : shortint;
.
.
.
{************** Variable Initialization and Intrinsic Call **************}
offset := 0;
maxinbuflen := 100;
inbuf := ' ';
READSTREAM (terminalid, offset, maxinbuflen, inbuf, actinbuflen, result);