Functions and CALL Routines under OpenVMS |
Modifies the characteristics of a channel that was previously
assigned by TTOPEN.
Category: |
Terminal-Access
|
OpenVMS specifics: |
All aspects are host-specific
|
TTCONTRL(control-specification,channel)
|
-
control-specification
-
is the control string as described for the
TTOPEN function. The syntax for control-specification
is the same as for TTOPEN, except that the DEVICE= attribute
cannot be changed. The new characteristics take effect on the next I/O
operation.
-
channel
-
is the channel variable that was returned
from the TTOPEN function.
If the TTCONTRL function executes successfully,
the return value is 0. Otherwise, the return value is the OpenVMS error
code that indicates why it failed.
The following example prompts the user for the password,
reads the password (without echoing it to the terminal), and then writes out
the password. The last step closes the channel:
length string $ 80;
input=' ';
chan=0;
rc=ttopen("device=tt echo",chan);
rc=ttwrite(chan,"0D0A"X||"Enter password: ");
rc=ttcontrl("noecho",chan);
rc=ttread(chan,input);
rc=ttcontrl("echo",chan);
rc=ttwrite(chan,"0D0A"X||"Password was: "||input);
rc=ttclose(chan);
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