macOS Programming Tips: what changed

Revision 1 to 2. Removed lines have a minus sign; added lines have a plus sign.

Old	New		Line
1	1		(macOS only)
2	2
3	3		## Choice of Lazarus LCL widgetsets
4	4
5	5		With macOS there are various widgetsets which can be used with Lazarus. Each has its strengths and weaknesses.
6	6
7	7		Carbon widgetset (see the [[Carbon Interface]] page)
8	8
9	9		\| Pros \| Cons \|
10	10		\|----\|----\|
11	11		\| All standard LCL controls working \| The entire Carbon framework has been deprecated by Apple. It is not available in 64 bit macOS applications. It was completely removed from macOS 10.15 Catalina (October 2019). The Carbon widgetset is no longer being developed. \|
12	12		\| No additional libraries or frameworks to install; uses Carbon framework included with macOS \| \|
13	13		\| Native macOS look and feel \| Only relevant to macOS \|
14	14
15	15		Cocoa widgetset (see the [[Cocoa Interface]] page)
16	16
17	17		<thead>
18	18
19	19		</thead>
20	20		<tbody>
21	21
22	22		uses the Cocoa framework included with macOS</td>
23	23
24	24		</tbody>
25	25
26	26		GTK widgetset
27	27
28	28		\| Pros \| Cons \|
29	29		\|----\|----\|
30	30		\| All standard LCL controls working \| Ugly; clunky common dialogs; doesn't look like Mac software \|
31	31		\| This widgetset is well tested \| Requires X11 and bulky GTK to be installed to run Lazarus or any GUI apps created with Lazarus \|
32	32		\| \| Have to start Lazarus at command line -- can't double-click Lazarus or place on dock (same with GUI apps) -- although see Creating an app bundle for a GTK application for how you can add this capability yourself. \|
33	33
34	34		Qt widgetset (see the [[Qt Interface Mac]] page)
35	35
36	36		\| Pros \| Cons \|
37	37		\|----\|----\|
38	38		\| Native macOS look and feel \| Requires the Qt interface framework to be installed to run app, which is rather large \|
39	39		\| All standard LCL controls working \| \|
40	40		\| The Qt widgetset also available for other platforms, so any effort put into developing Qt widgetset benefits multiple platforms \| \|
41	41		\| The Qt interface provides rich functionality \| \|
42	42		\| The Qt widgetset is easier to develop than other widgetsets \| \|
43	43
44	44		## Cross compiling macOS applications
45	45
46	46		See the [[Cross compiling]] article.
47	47
48	48		## Commonly used Unix commands
49	49
50	50		If you’re coming to macOS from Windows, you may find some of its Unix terminal commands confusing. Here are some equivalents. For more information about a command, enter `man command` in an Applications \> Utilities \> Terminal.
51	51
52	52		\| Action \| Windows command prompt window \| macOS Terminal or X11 window \|
53	53		\|----\|----\|----\|
54	54		\| Change to a different directory \| cd \| cd \|
55	55		\| Make a new directory \| mkdir \| mkdir \|
56	56		\| Delete a directory \| rmdir \| rmdir \|
57	57		\| List file directory in chronological order with detail \| dir /od \| ls -ltr \|
58	58		\| Copy a file, preserving its date-time stamp \| copy \| cp -p \|
59	59		\| Display contents of a text file \| type \| cat \|
60	60		\| Delete a file \| erase \| rm \|
61	61		\| Move a file \| move \| mv \|
62	62		\| Rename a file \| ren \| mv \|
63	63		\| Find a file \| dir /s \| find \|
64	64		\| Grep a file \| findstr \| grep \|
65	65		\| Display differences between two text files \| fc \| diff \|
66	66		\| Change file attributes \| attrib \| chmod \|
67	67		\| “Super-user” root authorization \| N/A \| sudo \|
68	68		\| Create symbolic link to a file or directory \| mklink \| ln \|
69	69		\| Shrink executable file size \| strip (included w/ Free Pascal) \| strip \|
70	70
71	71		## Useful commands and tools included with macOS
72	72
73	73		open
74	74
75	75		See the [[macOS Open Sesame]] article for the many and varied uses of the macOS `open` command.
76	76
77	77		zip / unzip
78	78
79	79		These are standard command-line zip archive compression/uncompression utilities.
80	80
81	81		Console
82	82
83	83		Drag the Console application from `/Applications/Utilities` and drop it on the dock so you always have it handy. Launch it whenever you want to see messages or errors output to the console by GUI apps (for example, when they crash). Invaluable for debugging.
84	84
85	85		Activity Monitor
86	86
87	87		The Activity Monitor application is also in `/Applications/Utilities` and is useful for monitoring CPU, memory, energy, network and disk usage.
88	88
89	89		otool
90	90
91	91		Use the otool command line utility to display information about an executable file or library. For example, enter the following to see information about Lazarus:
92	92
93	93		``` bash
94	94		cd /usr/local/share/lazarus
95	95		otool –L lazarus
96	96		```
97	97
98	98		This shows that Lazarus is dependent on various libraries in `/usr/lib` and `/System/Library/Frameworks/`, as you would expect. Open a Terminal and type `man otool` to view its manual page.
99	99
100	100		install_name_tool
101	101
102	102		Use install_name_tool with the –change switch to change where an executable file or library looks for a library that it requires. Open a Terminal and type `man install_name_tool` to view its manual page.
103	103
104	104		iconutil
105	105
106	106		Use the iconutil command line utility in `/usr/bin/` to create icon files (.icns) for use with your .app bundles. Open a Terminal and type `man iconutil` for its manual page.
107	107
108	108		pkgbuild, productbuild / Disk Utility
109	109
110	110		Use these utilities to create disk image (.dmg) files for deploying your applications. See [[Deploying Your Application]] for more information.
111	111
112	112		Command line tools `pkgbuild` and `productbuild` are in `/usr/bin/`. Disk Utility is in `/Applications/Utilities`. You can drag and drop Disk Utility on the dock.
113	113
114	114		A popular third party option is the GUI application [Packages](http://s.sudre.free.fr/Software/Packages/about.html) which creates .pkg installer archives.
115	115
116	116		PlistBuddy
117	117
118	118		The command line utility `PlistBuddy`, which is found in `/usr/libexec/`, may be used to read and modify the values inside of [[macOS property list files\|property list files]].
119	119
120	120		Script Editor / osascript
121	121
122	122		Use the Script Editor application to edit, compile and run AppleScript files. It’s located in `/Applications/Utilities/`.
123	123
124	124		Use the command line utility osascript from `/usr/bin/` to execute an AppleScript command or file from the command line or from a script file. For more information, enter `man osascript` in a Terminal to view its manual page.
125	125
126	126		latency
127	127
128	128		The latency diagnostic command line utility found in `/usr/bin/` monitors scheduling and interrupt latency measuring the number of context switches and interrupts, and reporting on the resulting delays. Open a Terminal and type `man latency` to view its manual page.
129	129
130	130		fs_usage
131	131
132	132		The fs_usage diagnostic command line utility reports system calls and page faults related to filesystem activity in real-time. The output displays the timestamp, system call, filename, elapsed time and name of the process. Open a Terminal and type `man fs_usage` to view its manual page.
133	133
134	134		Safari
135	135
136	136		Yes, I know, it is a web browser - but it is more. You can read manual pages with it too. So, rather than opening a Terminal and then typing `man 3 pause`, you can simply type `x-man-page://3/pause` into Safari's URL field and access the man page that way. Unfortunately recent version of Safari now ask you if you want to allow Safari to open the Terminal and this new security behaviour cannot be turned off and your choice is not remembered.
137	137
138	138		sc_usage
139	139
140	140		The sc_usage command line utility samples system calls and page faults, displaying them onscreen. Open a Terminal and type `man sc_usage` to view its manual page.
141	141
142	142		vm_stat
143	143
144	144		The vm_stat command line utility displays virtual memory statistics. Open a Terminal and type `man vm_stat` to view its manual page.
145	145
146	146		DevToolsSecurity
147	147
148	148		The DevToolsSecurity command line utility changes the security authorisation policies for use of the Apple-code-signed debugger and performance analysis tools on development systems. See further [[lldb\|DevToolsSecurity]].
149	149
150	150		## Cross-platform considerations
151	151
152	152		When you plan to compile the same application for different widget sets (eg Windows, GTK and Cocoa) or plan to use multiple languages, you should layout the controls on your form(s) using the [[Anchor Sides\|anchor editor]] and set the [[Autosize / Layout\|AutoSize]] property of your controls to True. Doing this from the beginning will save you a lot of frustrating layout problems later.
153	153
154	154		## Apple-specific UI elements
155	155
156	156		The Apple user interface in macOS has a number of unique features (eg the Dock, Apple main menu bar, sheets, drawers, user notifications, etc). For details on how to provide these non-cross-platform features in your applications, see the article [[Apple-specific UI elements]].
157	157
158	158		## Setting environment variables for an application
159	159
160	160		On macOS, the normal way to set any environment variables needed by an application is to set them in the LSEnvironment property of your application's [[macOS property list files\|Info.plist]] file.
161	161
162	162		## How to obtain the path to the Bundle
163	163
164	164		``` pascal
165	165
166	166		{$mode objfpc}{$H+}
167	167		{$modeswitch objectivec1}
168	168
169	169		...
170	170
171	171		uses
172	172		CocoaAll; // for NSBundle
173	173
174	174		...
175	175
176	176		function GetBundlePath: string;
177	177		begin
178	178		Result := NSBundle.mainBundle.bundlePath.UTF8String;
179	179		end;
180	180		```
181	181
182	182		This returns the full path up to and including the application bundle name (eg `/Users/Me/MyApp.app`).
183	183
184	184		Related: [[Locating the macOS application resources directory]].
185	185
186	186		## Determining where to store files
187	187
188	188		## Determining if a file is readable
189	189
190	190		The Lazarus function [fileisreadable](https://lazarus-ccr.sourceforge.io/docs/lazutils/lazfileutils/fileisreadable.html) reports if the user has read permissions for the specified file. However, modern versions of macOS will restrict [access to the following locations](https://developer.apple.com/library/archive/documentation/Security/Conceptual/AppSandboxDesignGuide/AppSandboxInDepth/AppSandboxInDepth.html):
191	191
192	192		- The app container directory. Upon first launch, the operating system creates a special directory for use by your app—and only by your app—called a container. Each user on a system gets an individual container for your app, within their home directory; your app has unfettered read/write access to the container for the user who ran it.
193	193		- App group container directories. A sandboxed app can specify an entitlement that gives it access to one or more app group container directories, each of which is shared among all apps with that entitlement.
194	194		- User-specified files. A sandboxed app (with an appropriate entitlement) automatically obtains access to files in arbitrary locations when those files are explicitly opened by the user or are dragged and dropped onto the application by the user.
195	195		- Related items. With the appropriate entitlement, your app can access a file with the same name as a user-specified file, but a different extension. This can be used for accessing files that are functionally related (such as a subtitle file associated with a movie) or for saving modified files in a different format (such as re-saving an RTF flat file as an RTFD container after the user added a picture).
196	196		- Temporary directories, command-line tool directories, and specific world-readable locations. A sandboxed app has varying degrees of access to files in certain other well-defined locations.
197	197
198	198		At the moment, there appears to be no reliable API to determine if a file is readable in all situations. Apple's own isReadableFileAtPath method is essentially a wrapper around the BSD access system call and does not take into account the various security and privacy features that Apple has added since macOS 10.0. Below, is a brute force method that determines if a file is readable by physically reading the first byte of data from the file. This is necessarily slower than simply reading the file permissions, but does provide a robust solution:
199	199
200	200		``` pascal
201	201		function FileIsReadableByThisExecutable(const AFilename: string): boolean;
202	202		// macOS will block applications from reading files outside their sandbox
203	203		// therefore, simply knowing the user has read acces is not sufficient
204	204		// requires "uses LazFileUtils"
205	205		var
206	206		f: file;
207	207		b: byte;
208	208		begin
209	209		Result := lazfileutils.FileIsReadable(AFilename);
210	210		{$IFDEF Darwin}
211	211		if not Result then exit; //globally not readable
212	212		if FileSizeUtf8(AFilename) < 1 then exit(false);
213	213		AssignFile(f, AFilename);
214	214		{$I+}
215	215		try
216	216		FileMode := fmOpenRead; //Set file access to read only
217	217		Reset(f, 1);
218	218		if ioresult <> 0 then
219	219		exit;
220	220		b := 0;
221	221		BlockRead(f, b, sizeof(b));
222	222		CloseFile(f);
223	223		result := true;
224	224		except
225	225		result := false;
226	226		end;
227	227		{$ENDIF}
228	228		end;
229	229		```
230	230
231	231		Many system frameworks that provide access to [protected resources](https://developer.apple.com/documentation/bundleresources/information_property_list/protected_resources) have dedicated APIs for checking and requesting authorization to use those resources. This allows you to adjust your application’s behaviour depending on the current access it has. For example, if the user denies your application permission to do something, you can remove related elements from your user interface. Because a user can change authorization at any time using Settings, always check the authorization status of a feature before accessing it. In cases without a dedicated API, be prepared to gracefully handle access failures as above.
232	232
233	233		For an example of an authorization API, see [AVCaptureDevice API](https://developer.apple.com/documentation/avfoundation/avcapturedevice/1624613-authorizationstatus).
234	234
235	235		## Accessing system information
236	236
237	237		Sysctl provides an interface that allows you to retrieve many kernel parameters in macOS (and Linux and the BSDs). This provides a wealth of information detailing system hardware which can be useful when debugging user issues or simply optimising your application (eg to take advantage of threads on multi-core CPU systems). The NSProcessInfo class provides access to a collection of information about the current process. The IOKit framework implements non-kernel access to I/O Kit objects (eg to retrieve the Mac platform serial number and UUID). For full details and example code, see the article [[Accessing macOS System Information]].
238	238
239	239		## Retrieve username/ full username
240	240
241	241		The code to retrieve the current user's username (eg joe) or full username (eg Joe Bloggs) can be found in the article [[macOS Retrieve (full)username]].
242	242
243	243		## Making a beep
244	244
245	245		Procedure declaration:
246	246
247	247		``` pascal
248	248		procedure NSBeep; cdecl;
249	249		external '/System/Library/Frameworks/AppKit.framework/AppKit' name 'NSBeep';
250	250		```
251	251
252	252		To use it:
253	253
254	254		``` pascal
255	255		procedure MakeBeep;
256	256		begin
257	257		{$IFDEF DARWIN}
258	258		NSbeep;
259	259		{$ENDIF}
260	260
261	261		[...]
262	262		end;
263	263		```
264	264
265	265		You can also assign NSBeep to the [OnBeep](https://www.freepascal.org/docs-html/rtl/sysutils/onbeep.html) (TBeepHandler in the SysUtils unit), by setting it on Form creation.
266	266
267	267		This way you can call the regular [Beep](https://www.freepascal.org/docs-html/rtl/sysutils/beep.html) function (by default, Beep contains no implementation to actually produce a beep).
268	268
269	269		``` pascal
270	270		procedure TForm1.FormCreate(Sender: TObject);
271	271		begin
272	272		{$IFDEF DARWIN}
273	273		OnBeep := @NSbeep;
274	274		{$ENDIF}
275	275
276	276		[...]
277	277		end;
278	278		```
279	279
280	280		## Show application in all desktop spaces
281	281
282	282		An application defaults to showing only in the desktop space in which it was opened. To show your application in all desktop spaces for macOS 10.5+ (Leopard):
283	283
284	284		``` pascal
285	285		{$modeswitch objectivec1}
286	286
287	287		Uses CocoaAll ...
288	288
289	289		procedure TForm1.MenuItem35Click(Sender: TObject);
290	290		var
291	291		theWindow: NSWindow;
292	292		begin
293	293		theWindow := NSView(Form1.Handle).window; // Form1 is the name of the main form - adjust as necessary
294	294		theWindow.setCollectionBehavior(theWindow.collectionBehavior or NSWindowCollectionBehaviorCanJoinAllSpaces);
295	295		end;
296	296		```
297	297
298	298		## Launch/Toggle full screen
299	299
300	300		To toggle an application window full screen for macOS 10.7+ (Lion):
301	301
302	302		``` pascal
303	303		{$modeswitch objectivec1}
304	304
305	305		Uses CocoaAll ...
306	306
307	307		procedure TForm1.Button1Click(Sender: TObject);
308	308		var
309	309		Window: NSWindow;
310	310		begin
311	311		Window := NSView(Form1.Handle).window;
312	312		Window.toggleFullScreen(Nil);
313	313		end;
314	314		```
315	315
316	316		To launch your application full screen you can call the button event handler (as below) or move the button event handler code (above) to the form's on activate event handler:
317	317
318	318		``` pascal
319	319		procedure TForm1.FormActivate(Sender: TObject);
320	320		begin
321	321		Form1.Button1Click(Form1);
322	322		end;
323	323		```
324	324
325	325		## Locale settings (date & time separator, currency symbol, ...)
326	326
327	327		On macOS, like on other Unix platforms, the RTL does not load the locale settings by default. They can be initialised in three ways. See the article [[Locale settings for macOS]] for details.
328	328
329	329		## Accessibility for users with special needs
330	330
331	331		macOS includes a wide variety of features and assistive technologies, such as screen and cursor magnification, a full-featured screen reader, visual flash alerts, closed captioning support, and much more. Take advantage of these features to make your apps accessible to users with special needs. Please refer to the [[LCL Accessibility\|Accessibility]] article for more details.
332	332
333	333		## LCL FontDialog workaround
334	334
335	335		The FontDialog.OnApplyClicked event handler is not supported in macOS. So this code will have no effect (the message will not be shown):
336	336
337	337		``` pascal
338	338		procedure TForm1.Button1Click(Sender: TObject);
339	339		begin
340	340		FontDialog1.Execute;
341	341		end;
342	342
343	343		procedure TForm1.FontDialog1ApplyClicked(Sender: TObject);
344	344		begin
345	345		ShowMessage('Apply Clicked');
346	346		end;
347	347		```
348	348
349	349		The workaround is to restructure the code as follows:
350	350
351	351		``` pascal
352	352		procedure TForm1.Button1Click(Sender: TObject);
353	353		begin
354	354		if FontDialog1.Execute then
355	355		begin
356	356		ShowMessage('Apply Clicked');
357	357		end;
358	358		end;
359	359		```
360	360
361	361		## Coping with missing features across macOS versions
362	362
363	363		For an example of how to cope elegantly with new features in macOS which are missing from older macOS versions, see [[Accessing macOS System Information\|this example]].
364	364
365	365		## Updating a GUI from a secondary thread
366	366
367	367		Apple’s UI frameworks, and Cocoa in particular, can only be called from the main thread. This means that if you have a background threading process, it cannot interact with the user interface because all user interface objects are marked as not safe for threading. Touching the user interface from a background thread can cause all sorts of issues, including corruption of internal state, crashes, or inexplicable incorrect behaviour.
368	368
369	369		For example code implementing a solution to this issue, refer to the [[macOS NSURLSession\|Downloading files with graphical user interface feedback]] article.
370	370
371	371		## Using PrintDialog in Cocoa
372	372
373	373		PrintDialog is only partially implemented (July 2020) in Cocoa. As a result, this code does not display the dialog:
374	374
375	375		``` pascal
376	376		procedure TForm1.btnPrintDialogClick(Sender: TObject);
377	377		begin
378	378		if PrintDialog1.Execute then
379	379		Panel1.Invalidate;
380	380		end;
381	381		```
382	382
383	383		This code will display the dialog:
384	384
385	385		``` pascal
386	386		procedure TForm1.btnPrintDialogClick(Sender: TObject);
387	387		begin
388	388		PrintDialog1.Options:= PrintDialog1.Options + [poBeforeBeginDoc];
389	389		if PrintDialog1.Execute then
390	390		Panel1.Invalidate;
391	391		end;
392	392		```
393	393
394	394		## Detecting the Apple Command key
395	395
396	396		The Apple Command key is ssMeta. Heres' how to test for it being depressed:
397	397
398	398		``` pascal
399	399		procedure TForm1.FormKeyDown(Sender: TObject; var Key: Word; Shift: TShiftState);
400	400		var
401	401		ssCmd: TShiftStateEnum;
402	402		begin
403	403		// Define standard menu command key as ssCmd
404	404		{$IFDEF DARWIN}
405	405		ssCmd := ssMeta; // Apple
406	406		{$ELSE}
407	407		ssCmd := ssCtrl // FreeBSD, Linux, Windows
408	408		{$ENDIF}
409	409
410	410		if (ssCmd in Shift) then
411	411		Caption:='Command key pressed'
412	412		else
413	413		Caption := IntToStr(Key) + ' not the command key';
414	414		end;
415	415		```
416	416
417	417		## Updating the GUI from a non-main thread
418	418
419	419		Any attempt to provide user feedback to the graphical user interface from within a delegate method running on a secondary background thread will cause the application to die with a log entry similar to this:
420	420
421	421		` *** Terminating app due to uncaught exception 'NSInternalInconsistencyException',`\
422	422		` reason: 'NSWindow drag regions should only be invalidated on the Main Thread!'`
423	423
424	424		The cause? Apple’s UI frameworks, and Cocoa in particular, can only be called from the main thread. Touching the user interface from a background thread can cause all sorts of issues, including corruption of internal state, crashes, or inexplicable incorrect behaviour.
425	425
426	426		One solution may be found in the [[macOS NSURLSession]] article which also has a code example.
427	427
428	428		## Libraries
429	429
430	430		### Using a library in a Mac application
431	431
432	432		Many software projects use external libraries to complement their functionality. For example, OpenAL might be utilized to provide sound support, or FreeType might be utilized to provide font rendering support for FCL-Image. macOS already comes with a number of open source libraries installed, being that OpenAL is one of them. If one of these libraries is utilized, one should simply add the corresponding import unit to the uses clause and start using the library. To use other open source libraries which aren't included with macOS, the easiest way is by grabbing a pre-compiled library from the application bundle of popular open source applications. FreeType for example is included inside the application bundle from Gimp in the path `Gimp.app/Resources/lib/libfreetype.6.dylib`. Another option is downloading the source code from the library and building it manually, but compiling a C library is usually an unpleasant task for pure Pascal developers.
433	433
434	434		So, again in the previous example, let's say that an application requires the FreeType library. One can grab the libfreetype.6.dylib file from Gimp and then place it in a location of our source code tree, for example `../Mac/libfreetype.dylib` relative to the path of the main project file, which is where the executable is placed. To properly link the application the Free Pascal command line option `-Fl../Mac` should be added, so that this path is added to the library search path. The linker will then find the library in this location and read the install path which is written inside it. At runtime the linker will search for the library in this install path. To change the install path to our desired one, the command line application install_name_tool, which comes with the Apple Developer Tools, can be used. It can be utilized with the following command line command:
435	435
436	436		``` bash
437	437		install_name_tool libfreetype.dylib -id @executable_path/../Frameworks/libfreetype.dylib
438	438		```
439	439
440	440		One can then verify if this command worked by using the command:
441	441
442	442		``` bash
443	443		otool -D libfreetype.dylib
444	444		```
445	445
446	446		It should return the written path. When building the application bundle, we should copy the libfreetype.dylib file to the Frameworks sub-directory. The install_name_tool command uses the @executable_path macro to set an install path relative to the executable, which is inside the MacOS folder in the application bundle. Now the application can be built, the bundle and then the application can be run and it will load the library correctly from the application bundle.
447	447
448	448		### Using a library installed using fink
449	449
450	450		For using libraries, which were installed using fink, you need to add the path to the libraries. The default is `/sw/lib`. Adding the option `-Fl/sw/lib` to the command line tells the linker where to find the libraries. The resulting application is fine for distribution with fink, but in order to run without fink, you have to make a "standalone" version. There are several possibilities to achieve this, one of them will be outlined here:
451	451
452	452		- Copy the .dylib file into the application bundle, for example to the `Contents/MacOS/` next to the executable binary. Then, adjust the paths install_name_tool:
453	453
454	454		- Change the path of the library in the executable:
455	455
456	456		``` bash
457	457		install_name_tool -change /sw/lib/libfreetype.dylib @executable_path/libfreetype.dylib @executable_path/your_executable_binary
458	458		```
459	459
460	460		- Adjust the path in the library:
461	461
462	462		``` bash
463	463		install_name_tool -id @executable_path/libfreetype.dylib @executable_path/libfreetype.dylib
464	464		install_name_tool -change /sw/lib/libfreetype.dylib @executable_path/libfreetype.dylib @executable_path/libfreetype.dylib
465	465		```
466	466
467	467		The complete list of libraries in your executable can be obtained with:
468	468
469	469		``` bash
470	470		otool -L @executable_path/your_executable_binary \| grep version \| cut -f 1 -d ' '
471	471		```
472	472
473	473		For the list of libraries from fink only, without libraries from `/usr/lib` and `/System/Library`, use this command:
474	474
475	475		``` bash
476	476		otool -L @executable_path/your_executable_binary \| grep version \| cut -f 1 -d ' ' \| grep -v \/System\/Library \| grep -v \/usr\/lib
477	477		```
478	478
479	479		With this a script can be created which loops over all libraries from fink in the executable. Be aware of the fact that the libraries can call libraries from fink. You have to adjust them as well.
480	480
481	481		Another important point of libraries from fink is, that they have only one architecture, ie i386, ppc, aarch64, x86_64 or ppc64. For a universal application, you have to combine single architecture libraries with `lipo`.
482	482
483	483		### Dynamic Libraries
484	484
485	485		For the details of creating and using dynamic libraries, see [[macOS Dynamic Libraries]] and [[macOS Frameworks]].
486	486
487	487		### Static Libraries
488	488
489	489		For the details of creating and using static libraries, see [[macOS Static Libraries]].
490	490
491	491		### Which dynamic libraries are used?
492	492
493	493		A little known method for checking which dynamic libraries an executable uses is as simple as setting an environment variable. The macOS dynamic linker checks the following environment variables during the launch of each process.
494	494
495	495		\| Environment Variable \| Description \|
496	496		\|----\|----\|
497	497		\| DYLD_PRINT_TO_FILE \| This is a path to a (writable) file. Normally, the dynamic linker writes all logging output (triggered by DYLD_PRINT_* settings) to file descriptor 2 (usually stderr). This setting causes the dynamic linker to write logging output to the specified file. \|
498	498		\| DYLD_PRINT_LIBRARIES \| When this is set, the dynamic linker writes to file descriptor 2 (normally stderr) the filenames of the libraries the program is using. This is useful to make sure that your program is loading the dynamic libraries you want. \|
499	499		\| DYLD_PRINT_RPATHS \| Causes dyld to print a line each time it expands an @rpath variable and whether that expansion was successful or not. \|
500	500
501	501		For full details of many other environment variables and their effect, see the manual page for dyld (type `man dyld` in a Terminal).
502	502
503	503		### OpenSSL, LibreSSL, Secure Transport, Network Framework
504	504
505	505		Apple deprecated the use of the included OpenSSL libraries in Mac OS X 10.7 (Lion) in July 2011 and suggested that developers should either include the needed libraries in their application bundle or use the [Secure Transport API](https://developer.apple.com/documentation/security/secure_transport) which itself has now been deprecated in favour of the [Network Framework](https://developer.apple.com/documentation/network) introduced in macOS 10.14 (Mojave). Use of the Apple-provided OpenSSL and LibreSSL libraries by applications is strongly discouraged by Apple (see [this statement](https://developer.apple.com/library/archive/documentation/Security/Conceptual/cryptoservices/SecureNetworkCommunicationAPIs/SecureNetworkCommunicationAPIs.html#//apple_ref/doc/uid/TP40011172-CH13-SW3)).
506	506
507	507		In the FPC 3.0.4 release, when trying to load the unversioned `libcrypto.dylib` or `libssl.dylib`, macOS terminates the application with the error: "Invalid dylib load. Clients should not load the unversioned libssl dylib as it does not have a stable ABI.". The fix for that bug (see [Bug \#36484](https://bugs.freepascal.org/view.php?id=36484)) was included in FPC 3.2.0 which caused FPC to fall back to using LibreSSL v2.2 (`libssl.35.dylib`) from June 2015.
508	508
509	509		As of the FPC 3.2.0 release, FPC breaks the ability of macOS to connect to web sites using HTTPS with TLSv1.2 or TLSv1.3 protocols only, because it fails to load the most recent Apple included LibreSSL libraries. It uses the very old LibreSSL v2.2 because the two libraries (`libssl.35.dylib` and `libcrypto.35.dylib`) for that version have matching version numbers (like OpenSSL) whereas the more recent LibreSSL library versions have mismatching version numbers.
510	510
511	511		The issue has been fixed in FPC trunk (see [Bug \#37977](https://bugs.freepascal.org/view.php?id=37977)) and is included in FPC 3.2.2. However, it still uses the outdated Apple-included system libraries listed in the table below.
512	512
513	513		<thead>
514	514
515	515		</thead>
516	516		<tbody>
517	517
518	518		libssl.0.9.8.dylib + libcrypto.0.9.8.dylib</td>
519	519
520	520		libssl.0.9.8.dylib + libcrypto.0.9.8.dylib</td>
521	521
522	522		libssl.0.9.8.dylib + libcrypto.0.9.8.dylib</td>
523	523
524	524		libssl.39.dylib + libcrypto.38.dylib</td>
525	525
526	526		libssl.0.9.8.dylib + libcrypto.0.9.8.dylib</td>
527	527
528	528		libssl.39.dylib + libcrypto.38.dylib<br />
529	529		libssl.43.dylib + libcrypto.41.dylib</td>
530	530
531	531		libssl.0.9.8.dylib + libcrypto.0.9.8.dylib</td>
532	532
533	533		libssl.43.dylib + libcrypto.41.dylib<br />
534	534		libssl.44.dylib + libcrypto.42.dylib</td>
535	535
536	536		libssl.0.9.8.dylib + libcrypto.0.9.8.dylib</td>
537	537
538	538		libssl.43.dylib + libcrypto.41.dylib<br />
539	539		libssl.44.dylib + libcrypto.42.dylib<br />
540	540		libssl.46.dylib + libcrypto.44.dylib</td>
541	541
542	542		libssl.0.9.8.dylib + libcrypto.0.9.8.dylib</td>
543	543
544	544		libssl.43.dylib + libcrypto.41.dylib<br />
545	545		libssl.44.dylib + libcrypto.42.dylib<br />
546	546		libssl.46.dylib + libcrypto.44.dylib</td>
547	547
548	548		libssl.0.9.8.dylib + libcrypto.0.9.8.dylib</td>
549	549
550	550		libssl.43.dylib + libcrypto.41.dylib<br />
551	551		libssl.44.dylib + libcrypto.42.dylib<br />
552	552		libssl.46.dylib + libcrypto.44.dylib<br />
553	553		libssl.48.dylib + libcrypto.46.dylib</td>
554	554
555	555		</tbody>
556	556
557	557		All the more reason to not use the macOS supplied library versions and either include your own up-to-date library versions or use the Apple Network Framework when you need direct access to protocols like TLS, TCP, and UDP for your custom application protocols. For details of including your own dynamic libraries in FPC or Lazarus applications, refer to [[macOS Dynamic Libraries]].
558	558
559	559		You can continue to use the [[macOS NSURLSession\|NSURLSession API]], which is built on the Apple Network Framework, for loading HTTPS-based and URL-based resources. This does not use the OpenSSL or LibreSSL system-included libraries.
560	560
561	561		#### OpenSSL versions
562	562
563	563		As at September 2023, the latest OpenSSL stable version is the 3.0 series which is supported until 7th September 2026. This is also a Long Term Support (LTS) version. Note that OpenSSL 3.0+ has significant ABI changes.
564	564
565	565		The previous LTS version OpenSSL 1.1.1 was on life support until 11th September 2023 at which time all support ceased (see [OpenSSL 1.1.1 End of Life](https://www.openssl.org/blog/blog/2023/09/11/eol-111/)), so no more bug fixes for security problems.
566	566
567	567		All older OpenSSL versions (including 1.1.0, 1.0.2, 1.0.0, 0.9.8 and 0.9.7) have been out of support for much longer, contain multiple security vulnerabilities and should not be used if you value security and your reputation.
568	568
569	569		## Application deployment/distribution
570	570
571	571		### Creating Universal binaries
572	572
573	573		#### aarch64 or Intel x86_64
574	574
575	575		Lazarus will create an application tuned for a single CPU. With the [[Cocoa Interface]] version of the [[LCL]], this is either Apple Silicon aarch64 or Intel x86_64. You may want to distribute your application as a 'Universal Binary', allowing users that may have either an Apple Silicon ARM64 processor or Intel processor to use the application.
576	576
577	577		For the fun details details of creating universal binaries for these two processor architectures, see [[macOS Big Sur changes for developers\|Creating a universal binary for aarch64 and x86_64]].
578	578
579	579		#### PowerPC or Intel i386
580	580
581	581		Lazarus will create an application tuned for a single CPU. With the [[Carbon Interface]] version of the [[LCL]], this is either [[PowerPC]] or Intel i386 (32 bit). You may want to distribute your application as a 'Universal Binary', allowing users that may have either a PowerPC or Intel computer to use the application. To do this, you need to compile two versions of your application: one with PowerPC as the target CPU and one as Intel. Next, you need to stitch these two executables together using the macOS program "lipo" (installed with the other Xcode developer tools required by Lazarus). For example, consider two versions of the application 'myprogram'. One in the 'ppc' folder compiled for PowerPC and one in the 'intel' folder compiled for Intel CPUs. You can then combine these two into a universal application by running this command:
582	582
583	583		` lipo -create ./ppc/myproj ./intel/myproj -output ./myproj`
584	584
585	585		Now, copy the newly created application myproj to the MacOS folder inside your [[Application Bundle]].
586	586
587	587		A note on 64 bit binaries: Depending on the version of macOS and after corresponding (cross-)compilers are installed, programs which do not use the LCL can also be built as ppc64 or x86_64 binaries, in particular command line utilities. `lipo` is used in the same way to put them into universal binaries.
588	588
589	589		### Executable size optimisation
590	590
591	591		The normal way to optimise the size of your executable with Lazarus would be:
592	592
593	593		1\. Project \> Project Options \> Compilation and Linking
594	594
595	595		- Check Optimisation level 3 (-O3)
596	596		- Check Smaller rather than faster (-Os)
597	597		- Check Smart Linkable (-CX)
598	598		- Check Link smart (-XX)
599	599
600	600		2\. Project \> Project Options \> Debugging
601	601
602	602		- Uncheck all except Strip Symbols From Executable (-Xs)
603	603
604	604		An example (Xcode 11.3; macOS Mojave 10.14.6):
605	605
606	606		- MyApp compiled with Lazarus defaults (-O1) - executable size 12,011,600 bytes.
607	607		- MyApp compiled with (-O3) - executable size - executable size 12,011,600 bytes.
608	608		- MyApp compiled with (-O3) and (-Os) - executable size 12,011,592 bytes.
609	609		- MyApp compiled with (-O3), (-Os) and (-CX) - executable size 12,011,592 bytes.
610	610		- MyApp compiled with (-O3), (-Os), (-CX) and (-XX) - executable size 4,624,076 bytes!
611	611		- MyApp compiled with (-O3), (-Os), (-CX), (-XX) and (-Xs) - executable size 4,624,076 bytes.
612	612
613	613		Problem: Whoa! Stripping symbols from the executable *should have made a difference*. The reason it did not make any difference is that Apple removed the ability to strip the symbol table from an executable in Xcode 3.1 (2007 Leopard 10.5). Previously, in Xcode 2.5 (2005 Tiger 10.4), the linker could strip the symbol table from 32 bit executables. So, providing the (-Xs) option to the linker has no effect at all.
614	614
615	615		Solution: The strip command line utility will strip the symbol table. Manually running `strip MyApp` in a Terminal resulted in the executable size further reducing from 4,624,076 bytes to 2,922,396 bytes.
616	616
617	617		### Deploying an application for an older version of the operating system
618	618
619	619		When compiling an application on a specific macOS release without any special options, the application is only guaranteed to work on that particular major operating system release and later (eg when compiling under Snow Leopard 10.6.8, the application is only guaranteed to work on Snow Leopard 10.6.8 and later).
620	620
621	621		Here is an example of an error that you may encounter when running an application compiled for Leopard 10.5 under Tiger 10.4 in case you use the widestring manager:
622	622
623	623		dyld: Library not loaded: /usr/lib/libiconv.2.dylib
624	624		Referenced from: /Volumes/..../yourprogram
625	625		Reason: Incompatible library version: yourprogram requires version 7.0.0 or later, but libiconv.2.dylib provides version 5.0.0
626	626		Trace/BPT trap
627	627
628	628		Here is an example of an error that you may encounter when running an application compiled for Snow Leopard 10.6.8 under Snow Leopard 10.6.7:
629	629
630	630		`Runtime error 203`
631	631
632	632		#### FPC 2.6.2 and above
633	633
634	634		See the article [[FPC New Features 2.6.2\|Support for specifying and querying the deployment version]] which is current up to and including FPC 3.04.
635	635
636	636		For FPC 3.2 (aka fixes branch) see the article [[User Changes 3.2\|Default target macOS version]].
637	637
638	638		Adding custom options only when compiling for macOS
639	639
640	640		To add the above custom options only when compiling for macOS add to Project / Compiler options / IDE macros / Conditionals:
641	641
642	642		``` pascal
643	643		if TargetOS = 'darwin' then begin
644	644		UsageCustomOptions += ' -WM10.6';
645	645		end;
646	646		```
647	647
648	648		#### FPC 2.6.1 and below
649	649
650	650		See the [[FPC 2.6.1 macOS Targets]] article.
651	651
652	652		### Creating an app bundle for a GTK application
653	653
654	654		macOS needs an app bundle for an executable file in order to drop it on the dock or launch it by double-clicking. An app bundle is really just a special folder that can have the same name as the executable, but with an .app extension. Finder doesn't display the .app extension, although you'll see it if you use the UNIX `ls` command in a Terminal window to list the directory contents. For details of how to create an app bundle for a GTK application, see [[Creating an app bundle for GTK applications]].
655	655
656	656		### Code Signing
657	657
658	658		Before macOS Sierra users had the option to allow the installation of applications from "anywhere", "the App Store" and "identified developers". From macOS Sierra on, the "anywhere" option was removed. Thereafter, clicking on an application to run it results in a scary dialog being presented to your users stating: "YourApp can't be opened because it is from an unidentified developer. Your security preferences allow installations of only apps from the App Store and identified developers". The only dialog option is to close it.
659	659
660	660		Users can still run your application, but they have to know they can right-click or control-click on your application and then they get another scary dialog stating "YourApp is from an unidentified developer. Are you sure you want to open it?" but this time the dialog has an "open" button and a pre-focussed "cancel" button.
661	661
662	662		[[Code signing]] an application that has been written in Lazarus and Free Pascal requires only a few steps that are described in the article [[Code Signing for macOS]]. Note: You will need to pay Apple \$US 99 per year to be an "identified developer" and code sign your applications.
663	663
664	664		### Notarization
665	665
666	666		Beginning with macOS Mojave 10.14.5 all new or updated kernel extensions and all software from developers new to distributing with a Developer ID must also be notarized in order to run or users are prevented from running the application with a very scary dialog stating: "YourApp can't be opened because Apple cannot check it for malicious software. This software needs to be updated. Contact the developer for more information."
667	667
668	668		Beginning with macOS 10.15 Catalina (released in October 2019), notarization is required by default for all software. If your application is not notarised, your users get the very scary dialog stating: "YourApp can't be opened because Apple cannot check it for malicious software. This software needs to be updated. Contact the developer for more information." This is in addition to requiring the application to be code signed.
669	669
670	670		The steps to notarize an application are described in the article [[Notarization for macOS 10.14.5+\|Notarization for macOS 10.14.5%2B]].
671	671
672	672		### Deploying your application
673	673
674	674		See [[Deploying Your Application\|macOS Deployment]].
675	675
676	676		## Using stdout and stderr for logging and debugging
677	677
678	678		### Using a Terminal
679	679
680	680		Unix systems usually allow output to `stdout` and `stderr` for GUI applications (while for Windows it requires creating a console object, using the file handle as `stdout/stderr` or linking the application as a non-GUI). The output is really useful for debugging and logging purposes.
681	681
682	682		macOS GUI applications (the ones created by Lazarus) are deployed as [bundles](http://en.wikipedia.org/wiki/Application_bundle). The bundled application conceals the output. However, it is possible to see the output generated by a simple `WriteLn('Debug: Test')` or `WriteLn(stderr, 'Debug: error alert!');`, by launching the application bundle's executable from a Terminal. Here are the steps:
683	683
684	684		- Launch Terminal (found in Applications \> Utilities)
685	685		- Change to the project directory
686	686		- Launch the executable:
687	687
688	688		` $ ./MyApp.app/Contents/MacOS/MyApp`
689	689
690	690		- once MyApp is running, the output will be seen in the Terminal window.
691	691
692		-	~~<img src="OSXStdOutExample.png" title="OSXStdOutExample.png" width="550" />~~
	692	+	![](/wiki-images/0/0b/OSXStdOutExample.png)
693	693
694	694		This is especially useful when using Project Options \> Compiler Options \> Debugging when you have ticked the Other debugging info - Use Heaprtc unit (check for mem-leaks). The Terminal will show the report:
695	695
696	696		` Heap dump by heaptrc unit of ./MyApp`\
697	697		` 1441 memory blocks allocated : 99080/102040`\
698	698		` 1441 memory blocks freed : 99080/102040 `\
699	699		` 0 unfreed memory blocks : 0`\
700	700		` True heap size : 458752 (32 used in System startup)`\
701	701		` True free heap : 458720`
702	702
703	703		### Using the Console
704	704
705	705		It is also possible to see the output by using the native macOS `NSLog()` procedure which logs your error message to the Apple System Log facility. You can read the System Log in realtime using the Console utility (located in Applications \> Utilities). As there will be many message entries scrolling by, add MyApp as a process to the search window to filter the entries being shown. For example:
706	706
707	707		``` pascal
708	708		MyAudioPlayer := AVAudioPlayer.alloc.initWithContentsOfURL_error(url, @err);
709	709
710	710		if Assigned(MyAudioPlayer) then
711	711		MyAudioPlayer.play
712	712		else
713	713		NSLog(NSStr('Error in procedure PlayAudio(): %@'), err);
714	714		```
715	715
716	716		When the audio file is missing from the application's Resources directory, the following appears in the Console system log:
717	717
718	718		![](/wiki-images/1/15/NSLog_Console.png)
719	719
720	720		Note that the NSlog information also appears in the Terminal if you have opened the application as explained above.
721	721
722	722		## Troubleshooting
723	723
724	724		The following articles are relevant for troubleshooting application issues:
725	725
726	726		- [[Cocoa Debugging\|Cocoa debugging]]
727	727		- [[lldb\|Debugging with the macOS lldb debugger]]
728	728		- [[macOS Gatekeeper Debugging Tips]]
729	729		- [[LazLogger\|LazLogger (part of Lazarus) will log to a file]]
730	730		- [[Logging exceptions]]
731	731		- [[heaptrc\|Memory leak checking]]
732	732
733	733		Seek help in the forums:
734	734
735	735		- [[Forum\|How to use the Forums effectively]]
736	736		- [FPC and Lazarus Forums](https://forum.lazarus.freepascal.org)
737	737
738	738		Obscure native macOS error codes?
739	739
740	740		- [Look up Apple API errors quickly!](https://OSStatus.com)
741	741
742	742		Finally, if the issue is in Free Pascal or Lazarus and not your own code:
743	743
744	744		- [[How do I create a bug report]]
745	745		- [[Tips on writing bug reports]]
746	746
747	747		## Converting legacy Pascal code
748	748
749	749		Bxxx code macro replacements:
750	750
751	751		- BAnd(i,j) = ((i) and (j))
752	752		- BOr(i,j) = ((i) or (j))
753	753		- BXOr(i,j) = ((i) xor (j))
754	754		- Bsr(i,n) = ((i) shr (n))
755	755		- Bsl(i,n) = ((i) shl (n))
756	756		- BTST(i,n) = ((((i) shr (n)) and 1)=1)
757	757		- BSet(i,n) = i:=(i) or (1 shl (n))
758	758		- BClr(i,n) = i:=(i) and not (1 shl (n))
759	759
760	760		See also: [[Porting from Mac Pascal]].
761	761
762	762		## See also
763	763
764	764		- [[Portal:Mac\|Lazarus/FPC macOS Portal]] - more macOS tips and code snippets
765	765
766	766		- [[Installing Lazarus on macOS]]
767	767
768	768		## External Links
769	769
770	770		- [Apple developer documents](https://developer.apple.com/documentation/) - current and up to date
771	771
772	772		- [Apple archived developer documents](https://developer.apple.com/library/archive/navigation/) - dated, but often more helpful
773	773
774	774		- [Making Your Lazarus App Mac-Friendly](https://macpgmr.github.io/MacXPlatform/MacXPlatform_Part8.html) (Apple help info outdated)
775	775
776	776		- Using Xcode for Pascal projects, refer to [this page](https://macpgmr.github.io/ObjP/ProjectXC.html).
777	777
778	778		---
779	779		From the Free Pascal wiki, page "macOS Programming Tips", as it stood on 2023-09-13 after a change by Trev, out of the wiki's dump of 2024-05-26. Copyright stays with the author who wrote it, according to the old wiki's [[Licensing]] page. If you have concerns about this material, [message the admin](/wiki-contact).

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