I'm trying to build an android app that print orders in specified Epson printer model. It works but breaks when tried to print multiple orders in short time. the error is ERR_ILLEGAL
Using sendData() for print command.
I found in the manual repeatedly calling sendData() can break this for the doc PDF (page: 60)
But I can't figure out how to do this when I need multiple print in short time. This type of task has no issue in JS SDK
Any help will be highly appreciated.
Related
I am trying to create a util for logging.
I need to know the actual differences between print() vs debugPrint() and log().
Many answers I have seen are outdated or confusing. Also, some upvoted answers are contradict.
I am trying to print error messages in red color. I am using ANSI code to achieve it.
debugPrint("\x1B[31m HelloDebug \x1B[0m");
The above one print in red color.
But when i do the same using log(), its not printing in red color. Its escaping the ANSI code.
One thing I found out was log() has error parameter.
If i pass something as error , it handles red color by default.
Here in the first one using log, red is not coming because ANSI code is ignored. But in debugPrint using it's working fine. In third one it takes error red by default. But extra line is added even for empty string message.
Code:
Output:
Is it possible use ANSI code for making color text using log?
Because I have other ANSI code to make different color text.
I dont want use debugPrint because if I print some thing too frequently , the system ignore the logs.
After digging some time I found out that log function is implemented in c++ in the dart runtime.As the log function is external function in dart sdk.
external void log(
String message, {
DateTime? time,
int? sequenceNumber,
int level = 0,
String name = '',
Zone? zone,
Object? error,
StackTrace? stackTrace,
});
https://github.com/dart-lang/sdk/blob/main/runtime/lib/developer.cc
Also I see some different answers while digging.
The below answer says debugPrint only available inside widget class. Is it still true?
https://stackoverflow.com/a/52241553/9248098
EDIT:
While using debugPrint and when I launch app from Android studio terminal, the ANSI color is working in android but when I run it same in iOS its escaping the characters in same Android Studio terminal.
If ANSI code support is based on terminal support, I couldn't figure out why its having issue in same terminal in iOS.
It is well explained in this page Debugging Flutter apps programmatically
debugPrint() is similar to print() but with a throttles applied to prevents being dropped by Android’s kernel.
If you have linter setup on VSCode or other IDE, you will see this warning whenever you use print in your code. For more information, you can refer to Avoid print calls in production code.
To avoid the lint error, you can use kDebugMode with print or debugPrint instead.
if (kDebugMode) {
print('test print');
}
// OR
debugPrint('test debugPrint');
As for log(), it actually allows you to include more information on the logging output. For example, you can add the runtimeType and the relevant object in the log that can help you in debugging the code.
log(
'test log',
name: runtimeType.toString(),
error: myObj,
);
** btw I tried log with ANSI code log("\x1B[31m HelloDebug \x1B[0m");, it is working as expected.
I just cannot figure out how to show logging messages when running dart files from terminal.
Example example.dart:
import 'dart:developer';
void main() {
print('print');
log('log');
}
Expected output:
print
log
Actual output:
print
I tried calling dart example.dart, dart run --all example.dart, dart run --verbosity=all example.dart, and different values instead of all (info, ...).
But non of these produced any helpful error messages let alone the out print I expect.
APIs from dart:developer (such as log) are intended to interact with debugging tools:
Interact with developer tools such as the debugger and inspector.
It's not explicit from the documentation for log, but I'd expect it to send a log message only to an attached debugger, not to the console.
If you want logging output that is independent of a debugger, use package:logging and add a listener that calls print, as shown by the example.
I am creating a label printing function in a program that needs to create labels for the given information. I have created a label in Crystal Reports 9 but I'm having trouble printing it.
I don't want to save the label, I just want it to print directly after the system has created it.
Dim ap9 As craxdrt.Application
Dim rpt9 As craxdrt.Report
Dim dbt As craxdrt.DatabaseTable
Set ap9 = New craxdrt.Application
On Error GoTo errError2
Set iniFile = New CIniFile
On Error GoTo errError3
Set rpt9 = ap9.OpenReport(iniFile.pathReports & REPORT_LABEL_IN)
On Error GoTo errError4
For Each dbt In rpt9.Database.Tables
dbt.Location = iniFile.pathDbCosmet
If dbt.ConnectionProperties.count <= 5 Then
dbt.ConnectionProperties.Add "Database Password", iniFile.passwordCosmet
End If
Next
rpt9.RecordSelectionFormula = sFormula
rpt9.PrintOut False, CInt(txtPacksReceived.Text)
The following code allows me to select a printer
and after clicking 'Print' at that point I am shown another dialog
However, the code executes fine, there are no errors, but the print queue doesn't show any documents and the report doesn't print.
Is there some reason why I'm not able to print my labels?
I've had problems with Zebra printers in the past that all turned out to be driver related. Have you uninstalled the printer driver and reinstalled it? Otherwise try unplugging and removing the device, plugging it into a different port and trying again?
Most likely your report doesn't contain any data - some logical error in selection/suppression formulas or similar.
If you print to any other printer, does something print out? Tracing SQL (assuming your report is bound to SQL server), can you see issued query? Does it look correct?
I'm using LabVIEW and its VISA capabilities to control a Keithley 2635A source meter. Whenever I try to identify the device, it works just fine, both in reading and writing.
viWRITE(*IDN?) /* VISA subVI to send the command to the machine */
viREAD /* VISA subVI to read output */
However, as soon as I set the voltage (or current), it does so. Then I send the command to perform a measurement, but I'm not able to read that data, with the error
VISA: (Hex 0xBFFF0015) Timeout expired before operation completed.
After that, I can not read the *IDN? output either anymore.
The source meter is connected to the PC via a National Instrument GPIB-USB-HS adaptor.
EDIT: I forgot to add, this happens in the VISA Interactive Control program as well.
Ok, apparently the documentation is not very clear. What the smua.measure.X() (where X is the needed parameter) command does is, of course, writing the measurement outcome on a buffer. In order to read that buffer, however, the simple viREAD[] is not sufficient.
So basically the answer was to simply add a print command: this way I have
viWRITE[print(smua.measure.X())];
viREAD[]
And I don't have the error anymore. Not sure why such a command is needed, but that's that. Thank you all for your time answering me.
As #Tom Blodget mentions in the comments, the machine may not have any response to read after you set the voltage. The *IDN? string is both command and query. That is, you will write the command *IDN? and read the result. Some commands do not have any response to read. Here's a quick test to see if you should be reading from the instrument. The following code is in python; I made up the GPIB command to set voltage.
sm = SourceMonitor()
# Prints out IDN
sm.query('*IDN?')
# Prints out current voltage (change this to your actual command)
sm.query('SOUR:VOLT?')
# Set a new voltage
sm.write('SOUR:VOLT 1V')
# Read the new voltage
sm.query('SOUR:VOLT?')
Note that question-marked GPIB commands and the query are used when you expect to get a response from the instrument. The instrument won't give a response for the write command. Query is a combination of write(...) and read(...). If you're using LabView, you may have to write the write and read separately.
If you need verification that the machine received your instruction and acted on it, most instruments have the following common commands:
*OPC? query to see if the operation is complete
SYST:ERR? query to see if any error was generated
Add a question mark ? to the end of the GPIB command used to set the voltage
For debugging purposes it would be great to be able to see just what you are getting back from the map method. Is this possible in ruby?
To do this in the Mongo shell, you can define you own debug version of the emit() function to print trace information.
function emit(k, v) {
print("emit");
print(" k:" + k + " v:" + tojson(v));
}
Check out Troubleshooting MapReduce in the MongoDB docs for more info.
I know the Mongo documentation recommends defining your own emit function, but I find it easier to instead use print() directly in my map- and reduce-functions while I watch Mongo's log.
Just put any print()'s in your code, run tail -f /var/log/mongodb/mongodb.log, then run your code. You should see the print()'s output to the console.
Here's a few of the benefits:
Ability to debug the reduce() function – defining your own emit() doesn't help here
No need to define the emit() function every time you fire up the mongo console
Write your code in your editor instead of going back and forth between console and IDE
Ability to do code generation and variable interpolation in your native language