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USupported on UNIX
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VSupported on OpenVMS
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xcall TTFLGS(flags[, control])
Arguments
flags
The terminal-oriented flags. Each flag is a single digit, and the digit positions are assigned ordinal numbers from right to left. Thus, the low-order digit is digit number one. Synergy DBL examines the flags value digit by digit to determine which flags are set, and hence, which functions are to be performed. For optimal performance, flags should be a zoned decimal field or literal. The Discussion contains a detailed description of the flags and their meanings. (n)
control
(optional) A value that controls how the individual digit positions in the flag specification value are interpreted. If control is not specified, each digit in flags is interpreted as follows: (n)
Reset the associated flag.
Set the associated flag.
Leave the associated flag unmodified, where n is any other decimal number.
We recommend that you use the control value when setting and resetting your flags values. If control is present, its value is interpreted as follows:
Reset all flags whose corresponding digit position contains a nonzero number. Leave all other flags unmodified.
Set all flags whose corresponding digit position contains a nonzero number. Leave all other flags unmodified.
Set the flags variable to a value that reflects the current settings of zero if the associated flag is currently reset or to one if the flag is set. If the length of the variable is less than four characters, the settings are returned as in a decimal-to-decimal assignment. (See Moving decimal/packed data to a decimal/packed destination for more information about decimal-to-decimal assignments.)
The TTFLGS subroutine sets terminal-oriented flags.
When program execution begins, all program-controlled flags are normally reset, and the program can alter them as needed. The flag settings are not preserved across program chaining. In effect, the STOP statement resets all of the flags as its last action, even if another program is being started. The flag settings in one program do not affect the settings in a program that is running concurrently from another terminal.
Synergy DBL interprets the flags argument as if it were storing it to a d4 variable. All rules that apply when storing to a decimal variable apply here. For example, if you specify
xcall ttflgs(01)
Synergy DBL interprets your argument as 0001. (All flags corresponding to these zeros are cleared.)
Remember that the rightmost digit in the flag specification string corresponds to flag number one, as shown in the figure below. You don’t have to specify a flag if that flag and all flags to its left have a value of zero.
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A more detailed description of the flags is provided below.
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Flags for TTFLGS |
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Flag |
Behavior when set |
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1 |
(OpenVMS) The terminal driver does not perform data interpretation or formatting on data output by a DISPLAY, WRITES, or FORMS statement to the terminal. When flag 1 is reset, data interpretation and formatting do occur. |
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2 |
(OpenVMS) If Ctrl+O is in effect, it is disabled before a DISPLAY, WRITES, or FORMS statement to the terminal is performed. When flag 2 is reset, Ctrl+O is enabled. |
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3 |
(OpenVMS) The type-ahead buffer is purged before a READS or ACCEPT statement from the terminal is performed. When flag 3 is reset, the type-ahead buffer is not purged. |
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4 |
Valid ANSI escape sequences are recognized as terminators for READS, and they return the corresponding sequence code. (The escape character is not considered a valid terminator for READS.) When flag 4 is reset, ANSI escape sequences are not recognized. Flag 4 also understands the SS3 (143) and CSI (155) form of escape keys. |
The table below specifies the return code number corresponding to each key on a VT220 keyboard.
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Key name |
Code |
VT200 |
VT100 |
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Keypad keys |
PF1 |
256 |
PF1 |
PF1 |
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PF2 |
257 |
PF2 |
PF2 |
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PF3 |
258 |
PF3 |
PF3 |
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PF4 |
259 |
PF4 |
PF4 |
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KP0 (0) |
260 |
0 |
0 |
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KP1 (1) |
261 |
1 |
1 |
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KP2 (2) |
262 |
2 |
2 |
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KP3 (3) |
263 |
3 |
3 |
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KP4 (4) |
264 |
4 |
4 |
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KP5 (5) |
265 |
5 |
5 |
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KP6 (6) |
266 |
6 |
6 |
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KP7 (7) |
267 |
7 |
7 |
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KP8 (8) |
268 |
8 |
8 |
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KP9 (9) |
269 |
9 |
9 |
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Enter (Return) |
270 |
Enter |
Enter |
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Minus (–) |
271 |
– |
– |
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Comma (,) |
272 |
, |
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Period (.) |
273 |
. |
. |
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Cursor positioning keys |
Up |
274 |
Up Arrow |
Up Arrow |
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Down |
275 |
Down Arrow |
Down Arrow |
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Left |
276 |
Left Arrow |
Left Arrow |
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Right |
277 |
Right Arrow |
Right Arrow |
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Function keys |
F6 |
286 |
F6 |
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F7 |
287 |
F7 |
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F8 |
288 |
F8 |
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F9 |
289 |
F9 |
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F10 |
290 |
F10 |
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F11 |
291 |
F11 |
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F12 |
292 |
F12 |
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F13 |
293 |
F13 |
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F14 |
294 |
F14 |
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Help |
295 |
Help |
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Do |
296 |
Do |
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F17 |
297 |
F17 |
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F18 |
298 |
F18 |
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F19 |
299 |
F19 |
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F20 |
300 |
F20 |
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Editing keys |
Home/Find |
311 |
Find |
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Insert_Here |
312 |
Insert Here |
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Remove |
313 |
Remove |
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End/Select |
314 |
Select |
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Prev_Screen |
315 |
Prev Screen |
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Next_Screen |
316 |
Next Screen |
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Other |
Unknown |
511 |
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On OpenVMS, terminal I/O is implemented using the OpenVMS $QIO System Service. You can find additional information on the use of the flags set by TTFLGS in your OpenVMS I/O User’s Reference Manual. The set flags modify the I/O function code passed to the $QIO service as follows:
- Flag 4 sets the IO$M_ESCAPE modifier for Read QIOs, which instructs the terminal driver to validate incoming escape sequences.
- Flag 3 sets the IO$M_PURGE modifier for Read QIOs, which allows the program to throw away any characters that may have been typed ahead but not yet read by the program.
- Flag 2 sets the IO$M_CANCTRLO modifier for Write QIOs, which allows the program to force data to be displayed, even though the user may have previously pressed Ctrl+O to turn output off.
- Flag 1 sets the IO$M_NOFORMAT modifier for Write QIOs, which allows the program to bypass the formatting normally performed by the terminal driver, such as line wrapping. Setting this flag may allow performance gains when using the DMA transfer mode supported by certain terminal line controllers, such as DMF-32.
Examples
In the following example, the ACCEPT statement accepts either a normal key or a function key. For example, if the user presses the A key, code will contain a decimal 65 (the ASCII code for “A”). If the user presses the Up Arrow key, code will contain a decimal 275 (the code for an Up Arrow).
record
code ,d3
proc
open(1, i, "TT:")
xcall ttflgs(1000) ;Turn on esc seq processing
accept(1, code)
In the example below, the ACCEPT statement accepts either a normal key or a function key. However, since achar cannot hold the code for a function key, an escape character is returned to achar. The RSTATD subroutine is then called to retrieve the code for the function key. A single escape character is not a valid escape sequence and is not accepted when escape sequence processing is enabled.
record
size ,d1
code ,d3
achar ,a1
proc
open(1, i, "TT:")
xcall ttflgs(1000) ;Turn on esc seq processing
xcall rstatd(size, code)
In the following example, READS accepts a string of characters (up to the size of buffer). The string can be terminated by one of the normal terminator keys (return, line feed, form feed, or vertical tab), by filling the buffer (if the appropriate FLAGS digit is set), or by a function key. The RSTATD subroutine is then called to retrieve the code for the terminator. Code contains either the decimal code for one of the normal terminator keys or a function key code.
record
size ,d2
code ,d3
buffer ,a20
proc
open(1, i, "TT:")
xcall ttflgs(1000)
reads(1, buffer) ;Turn on esc seq processing
xcall rstatd(size, code)
