HP 3000 Manuals HP 3000 Manuals
WRITESTREAM
WRITESTREAM
creates the data stream that your program on the HP 3000 sends to the
host (LU.T2 emulation only).
Syntax
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| |
| I I I CA I |
| WRITESTREAM (terminalid, offset, outbuflen, outbuf, 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 specifying the offset, in characters, into the internal screen
image. The data transfer starts at the location you specify in offset.
The first character has an offset value of zero. The offset parameter
must be zero when the DBCS option to the OPEN3270 intrinsic is enabled.
outbuflen (input)
Integer specifying the length of the character string outbuf, in
characters. The maximum values for outbuflen are as follows:
540 bytes for 480-character screens
2160 bytes for 1920-character screens
3870 bytes for 3440-character screens
outbuf (input)
Character array that contains the data stream to be written to the
internal screen image.
result (output)
The following values can be generated by the WRITESTREAM intrinsic:
0 = Successful completion.
1 = Device not open.
9 = Host modified screen since 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)
44 = WRITESTREAM called during LU.T1 session.
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
The WRITESTREAMintrinsic can be used only during LU.T2 emulation and only
in transparent mode. To open a device in transparent mode, call the
OPEN3270 intrinsic with bit 14 of the flags parameter set to 1.
To send data to the host, call WRITESTREAM to create the data stream,
then call TRAN3270 to transmit it to the host. WRITESTREAM accepts an
array of characters destined for the host and puts these characters into
your internal screen image. You must supply the terminal identifier, the
array of characters, and the number of characters in the data stream.
The maximum length of the outbuf string (and the maximum value for the
outbuflen parameter) is as follows:
540 bytes for 480-character screens
2160 bytes for 1920-character screens
3870 bytes for 3440-character screens
After your application receives the initial screen from the host (for
example, the CICS or TSO welcome screen), it is communicating over the
LU-SSCP session. At this point, data you write to the internal screen
image with the WRITESTREAM intrinsic will be appended to the end of the
data received from the host. When you call TRAN3270 to transmit the
internal screen image to the host, data is read starting from the first
position after the last data received from the host. Therefore, you must
set the offset parameter of the WRITESTREAM intrinsic to the length of
the last data stream received from the host. (The offset in your
WRITESTREAM call should equal the actinbuflen from your last call to
READSTREAM).An offset of zero would place the data at the beginning of
the internal screen image, before the position where reading begins, and
an empty RU would be sent to the host.
After the BIND, when the LU-LU session has been established, the internal
screen image is read from the beginning (position 0). When you call
TRAN3270, the entire screen image, beginning at position 0, is
transmitted to the host. Therefore, while your application is
communicating over the LU-LU session, you should set the offset parameter
of the WRITESTREAM intrinsic to 0.
If you make multiple calls to WRITESTREAM before you call TRAN3270, each
write must begin where the last one left off. In other words, the offset
of the second WRITESTREAM call should be the outbuflen value from the
first call, the offset of the third call should be the sum of the
outbuflen values from the previous two calls, and so on.
When sending data to the host, your WRITESTREAM buffer needs to contain
only the data to be transferred. SNA IMF divides this data into frames
and adds the SDLC and SNA protocol headers. The AID key and cursor
address, which you specify in your call to TRAN3270, are inserted at the
front of the first frame. You can suppress insertion of the AID key and
cursor address in transparent mode. See the description of TRAN3270,
earlier in this chapter, for more information.
If cursor suppression is not used, and you are sending the CLEAR key or a
PA key during an LU.T2 session, call WRITESTREAM with an outbuf of length
zero before calling TRAN3270. In transparent mode, SNA IMF will not
check the AID key to determine whether it is the CLEAR key or a PA key.
In non-transparent mode, no data is sent with the CLEAR or PA keys.
Call WRITESTREAM only in transparent mode. See chapter 2 for information
about transparent mode.
COBOL Calling Sequence
CALL "CWRITESTREAM" USING TERMINALID OFFSET OUTBUFLEN OUTBUF RESULT. (on
MPE V and in compatibility mode on MPE XL)
CALL INTRINSIC "WRITESTREAM" USING TERMINALID OFFSET OUTBUFLEN OUTBUF
RESULT. (in native mode on MPE XL)
All parameters are numeric data items except OUTBUF, which is an
alphanumeric data item.
FORTRAN Calling Sequence
CALL WRITESTREAM (TERMINALID, OFFSET, OUTBUFLEN, OUTBUF, RESULT)
All parameters are integer variables except OUTBUF, which is a character
array.
BASIC Calling Sequence
CALL BWRITESTREAM (T, O1, L9, O$, R) (on MPE V and in compatibility mode
on MPE XL)
CALL WRITESTREAM (T, O1, L9, O$, R) (in native mode on MPE XL)
All parameters are integer variables except O$, which is a string
variable.
SPL Calling Sequence
WRITESTREAM (TERMINALID, OFFSET, OUTBUFLEN, OUTBUF, RESULT)
All parameters are integer data items except OUTBUF, which is a byte
array.
Pascal Calling Sequence
WRITESTREAM (TERMINALID, OFFSET, OUTBUFLEN, OUTBUF, RESULT);
All parameters are short integer variables except for OUTBUF, which is a
packed array of char.
C/XL Calling Sequence
WRITESTREAM (&TERMINALID, &OFFSET, &OUTBUFLEN, OUTBUF, &RESULT);
All parameters are of type short, except OUTBUF, which is an array of
characters (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 **************************}
const
MAXBUFLEN = 2160; { maximum buffer length for }
{ 1920-character screens }
{ in transparent mode }
.
.
.
type
shortint = -32768..32767; { global type, two bytes (half word) }
var
terminalid : shortint; { value returned by OPEN3270 intrinsic }
result : shortint;
.
.
.
procedure WRITESTREAM; intrinsic;
.
.
.
{************************** Local Declarations **************************}
var
offset : shortint; { All WRITESTREAM variables except }
outbuflen : shortint; { terminalid and result are local. }
outbuf : packed array[1..MAXBUFLEN] of char;
.
.
.
{************** Variable Initialization and Intrinsic Call **************}
offset := 0;
outbuflen := 51;
outbuf := 'logon applid(tso) data(sales/sales) logmode(imf2k) ';
WRITESTREAM (terminalid, offset, outbuflen, outbuf, result);