I have created sd_bus and then registered for signals by specifying match using sd_bus_add_match() and getting signals from sd-bus. Now I want to know how to stop getting the events for specific match without invoking sd_bus_close().
As far as i can tell, reading source code, it seems you have got to pass a sd_bus_slot** to sd_bus_add_match; it will create one for you with type BUS_MATCH_CALLBACK.
Once you're done, just unref your sd_bus_slot and it will take care of destroying match and freeing all resources. See here: https://github.com/systemd/systemd/blob/a7753693547233e4a1d6e10b1a8f6515a477f227/src/libsystemd/sd-bus/bus-slot.c#L68 (note that bus_slot_disconnect is called by sd_bus_slot_unref().
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I have worked a great deal with the text system in Objective-C for macOS/iOS (e.g. NSTextView, NSTextStorage, etc.) I am now experimenting with GTK3 to see how well I can translate my project for use on Linux, etc.
I am brand new to using GTK, but after a few days of Google time and experimenting, I have a working text editor prototype with my custom code plugged in.
The problem is this -- I need to be able to detect when a user highlights a section of text, and then replaces it with other text (e.g. a keystroke). This is distinct from highlighting a section of text, hitting the delete key, and then typing the new text. A specific use example would be highlighting a word, then typing a double quote character in order to wrap the word in quotes (e.g. foo becomes "foo").
In Cocoa, one would receive replaceCharactersInRange: that indicates the range originally selected, as well as the new string to replace it with. I can then detect the presumed intent of the user based on the information received.
In GTK, it seems that we receive a delete-range signal, followed by a separate insert-text signal. Because of this separation, the code in the "insert" section has no way of knowing that the user intended to replace text, not insert new text.
I used the following to receive the signals above:
g_signal_connect(buffer, "insert-text", G_CALLBACK(insert_text_cb), NULL);
g_signal_connect(buffer, "delete-range", G_CALLBACK(delete_range_cb), NULL);
Is there something else I can do in order to tell that there is a delete, followed by an insert as part of the same user action?
Thanks for any pointers offered!
Instead of trying to correlate the delete and insert events, I would suggest creating a GAction for your desired action (e.g. toggle quotes around the selected text) and setting its shortcut key to " using gtk_application_set_accels_for_action().
For more information, check out this HowDoI wiki page.
No answers over the last month, so I kept brainstorming and digging around. I finally came up with this, which works, but is not quite as elegant as I had hoped.
Handle delete-range signal as before, but keep track of the the deleted text for later (e.g. in char * deletedText).
Handle the insert-text signal as before, but if we have a string in deletedText then change the behavior to perform a replacement instead of an insertion. In my case, this actually meant inserting the deleted text back in, and then performing the replacement.
Add a callback for the end-user-action signal, which indicates that all delete/inserts associated with a particular action are complete. In this callback, free deletedText from above and set to NULL (to indicate that everything has been handled).
Again -- this works, but feels a bit inelegant. And depending on how complex your delete/insert routines are, it may slow the performance slightly since some steps have to be duplicated. A better solution would be to detect during the delete-range callback that there is a pending insert-text callback and handle both steps at once. I have thus far not been able to do that.
Is there a way to check for dead keys in the current layout? I am currently capturing the users input for a project I am doing. I created a map of all keys on the keyboard, but there seems to be no flag or whatsoever defining a key as dead or not. I use libxkb in my current code.
The layout is retrieved using
KeySym * keysyms = XGetKeyboardMapping(display_, keycode_low, keycode_high - keycode_low + 1, &num_keysym);
I understand you need to know which key will not directly produce a character, maybe because you are writing a game and do not want to have it use keys as input that would require another key to be pressed to produce some output (if so, please mention in the question)
Not through standard Xlib calls, to my knowledge, and definitely not without actually pressing the respective key. Composing is entirely done within Xlib, and transparent to the front end. (For its original purpose, it should be as transparent as possible to work properly, after all)
You could, however, do the same thing that Xlib does and parse through the various Compose configuration files starting with $HOME/.Xcompose. But that could be a tedious process.
On second thought, I am definitely not proposing the following:
You could, for each key you are looking for information, create a synthetic keypress event and feed it into XLookupString. Hand in an emptied XComposeStatus structure as well. If the structure returns modified, this could be a strong hint you have found a compose key. But it could also mean the server modifies it without any need..... If I were very desparate, I'd probably try.
I am involved in using the C API to interact with Lotus Notes and Lotus Domino. I'm running into issues when reading existing Notes out of an NSF. Specifically, reading TYPE_OBJECT fields and even more specifically, $FILE fields (though I'm sure all TYPE_OBJECT fields would fail if I had any others).
I'm using NSFItemInfo to get the summary data on the $FILE field (so I don't need the saved file, I need information about it such as its size, name, etc...).
If I create the Note in memory, Commit it, then read the $FILE field, everything works. If I change my unit test to read an existing Note (instead of creating it in memory), Lotus PANICS with an Invalid Handle Lookup message.
So I'm left feeling like there is something different about loading those fields when I create a Note from scratch Vs opening one already created. Even reading in an already created Note that my own code created gives me the same error, so I think I'm creating the Notes correctly.
I've explored the NSFNoteOpenExt's flags options and have attempted to open the Note with every possible flag described in OPEN_xxx and I always get the panics except when I open the Note with OPEN_ABSTRACT or OPEN_NOOBJECTS. The reason those don't error though, is because they open the Note without the $FILE fields at all, so when I see if the field exists I get a false and the code to read in TYPE_OBJECT fields is never executed.
Any ideas what I'm missing?
I'd provide code, but I'm actually using .NET interop to accomplish all this, and the code is spread across multiple files, etc.... If you have any questions please ask and I'll provide as much detail as I can.
Craig
I figured out the issue. It came from the fact that when using interop in C#, you can't call C macros. OSLockBlock is defined as a macro to another macro to a function. Essentially, it locks the BlockId.Pool pointer, then increments the pointer by BlockId.BlockHandle. I was mis-interpreting that macro logic to be first increment BlockId.Pool by BlockId.BlockHandle, then lock.
Essentially:
Lock(BlockId.Pool)+BlockId.BlockHandle Vs Lock(BlockId.Pool+BlockId.BlockHandle)
It's interesting that the latter would work when creating a new note with new attachments. I finally figured that out as well, BlockId.BlockHandle was always zero when doing that. So that's why that always worked.
This is a question which follows on from my previously answered question here
At first I assumed I had a problem with the way I was creating my events due to the handles for OpenEvent returning NULL, I have managed to find the real cause however I am not sure how to go about it.
Basically I use Visual Studio to launch both Process A and B at the same time, in the past my OpenEvent handle wouldn't work due to Process A looking for the address of the event a fraction of a second before Process B had time to make it.
My solution was to simply allow Process B to run before Process A, fixing the error.
The problem I have now is that Process B now reads events from Process A and as you expect it too returns a null handle when trying to open the events from Process A.
I am creating the events in WM_CREATE message of both processes, furthermore I also create a thread at the same time to open/read/act upon the events.
It seems if I run them at the same time they don't get chance to see each other, alternatively if I run one before the other one of them misses out and can't open a Handle.
Can anyone suggest a solution?
Thanks.
Just replace OpenEvent with CreateEvent. CreateEvent will open an Event instead of creating a new one it finds an existing event with the name passed to CreateEvent.
I encountered a bug that has me beat. Fortunately, I found a work around here (not necessary reading to answer this q) -
http://lists.apple.com/archives/quartz-dev/2009/Oct/msg00088.html
The problem is, I don't understand all of it. I am ok with the event taps etc, but I am supposed to 'set up a thread-safe queue) using MPQueue, add events to it pull them back off later.
Can anyone tell me what an MPQueue is, and how I create one - also how to add items and read/remove items? Google hasn't helped at all.
It's one of the Multiprocessing Services APIs.
… [A] message queue… can be used to notify (that is, send) and wait for (that is, receive) messages consisting of three pointer-sized values in a preemptively safe manner.