Debugger Console App: what changed

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

Old	New		Line
1	1		## Introduction
2	2
3	3		This page contains information on how to debug console applications in Lazarus. That is where to find the output (writeln) of your app, and where to type the input (readln).
4	4
5	5		This page was written for Lazarus 0.9.30 and above.
6	6
7	7		## Windows
8	8
9		-	On Windows, the application will open its own console window, just as it would outside the debugger. There is no need to do anything special apart from adding a `ReadLn;` before the application terminates so that the console window does not automatically close until you press <span class="kbd">Enter</span>.
	9	+	On Windows, the application will open its own console window, just as it would outside the debugger. There is no need to do anything special apart from adding a `ReadLn;` before the application terminates so that the console window does not automatically close until you press `Enter`.
10	10
11	11		## Linux
12	12
13	13		### Lazarus 0.9.30 / 0.9.30.2
14	14
15	15		Please see the notes in the#Mac section.
16	16
17	17		### Lazarus 0.9.31 / 1.0 and higher
18	18
19	19		You can open a console window from the menu: "View" =\> "Debug Windows" =\> "Terminal Output"
20	20
21	21		It shows the raw output of your application. Note it has no support for any escape sequences, as some terminals may have. Anything you type into this window will be sent to your application.
22	22
23	23		## Mac & Linux
24	24
25	25		Unfortunately there is currently no built-in support for debugging console applications.
26	26
27	27		Console applications do not have their own terminal, but use the terminal they were started from (the terminal of the shell they were started from). When started from within Lazarus, there is no such terminal. You can specify a "starter application" (like xterm) under menu "Run" =\> "Run parameters". however this only works if you start your application without a debugger. This does not work for debugging.
28	28
29	29		There are a couple of workarounds.
30	30
31	31		### Redirect output to file
32	32
33	33		In menu "Run" =\> "Run parameters": specify in "command line parameters":
34	34
35	35		` >/somedir/somefile`
36	36
37	37		Then outside Lazarus open a shell and run
38	38
39	39		``` bash
40	40		tail -f /somedir/somefile
41	41		```
42	42
43	43		### Redirect input and output to a pty (terminal)
44	44
45	45		Open a terminal outside of Lazarus and run
46	46
47	47		```bash>
48	48		pty
49	49		</syntaxhighlight>
50	50		On Ubuntu 18, the command is
51	51		<syntaxhighlight lang=
52	52		```
53	53
54	54		tty
55		-
56		-	~~</syntaxhighlight>~~
57	55
58	56		It should return something like
59	57
60	58		` /dev/pty/2`
61	59
62	60		The exact value depends on the OS and the number of terminals already open.
63	61
64	62		Note
65	63		The returned value is only valid as long as the terminal stays open, so if you open a new terminal next time you debug in Lazarus, you need to adapt all settings to the new value.
66	64
67	65		In menu "Run" =\> "Run parameters": specify in "command line parameters":
68	66
69	67		` >/dev/pty/2 </dev/pty/2`
70	68
71	69		If you want to use the terminal to send input to your application, then you may need to stop the shell in it from reacting to the input (unless you started a terminal without a shell). Run something like
72	70
73	71		``` bash
74	72		tail -f /some/empty/file/that/does/not/change
75	73		```
76	74
77	75		> Note: This means you still can't use ctrl-c in the input.
78	76
79	77		#### Debugger startup options
80	78
81	79		In the global options dialog, on the debugger page, you can specify parameters given to gdb (do *not* use the in/output redirect \> or \< here, which is meant for interactive bash but use something like --args).
82	80
83	81		It may be possible to specify the pty here, but there is currently no further info.
84	82
85	83		### gdbserver
86	84
87	85		Use the gdbserver based debugger. You can start gdbserver on the same computer as the IDE. Run gdbserver inside the terminal that you want to use for your stdout/stdin
88	86
89	87		### Lazarus 0.9.31
90	88
91	89		In the global options dialog, on the debugger page is an entry "ConsoleTty". You can enter the result of "pty" here. Then you do not need to specify any \< or \> redirects.
92	90
93	91		### Lazarus 2.x with LLDB on macOS aarch64
94	92
95	93		In the global options dialog, on the debugger page there is a "LaunchNewTerminal" option when LLDB is selected (currently the only option for this platform).
96	94
97	95		However if you tick that without making the following prerequisites, lldb (and thus Lazarus) will freeze.
98	96
99	97		1, First of all, check that your terminal shell is listed in the /etc/shells file.
100	98
101	99		You can check your current shell by this command:
102	100
103	101		``` bash
104	102		echo $SHELL
105	103		```
106	104
107	105		And list the current contents of this file by this command:
108	106
109	107		``` bash
110	108		cat /etc/shells
111	109		```
112	110
113	111		If you installed your shell e.g. via Homebrew, your shell is probably not on the list. In this case you can add it manually, to make the following commands will work.
114	112
115	113		If you have to edit this file, be extremely cautious, and do it on your own risk! You have been noticed!
116	114
117	115		2, (Optional step) If you use different terminal emulator than the default one, you can test the following command.
118	116
119	117		``` bash
120	118		osascript -e "tell application \"Terminal\" to do script \"echo lazarus\""
121	119		```
122	120
123	121		The system protection dialog should pop-up, about do you allow xy application to control the terminal. You should answer yes, and check that the freshly popped-up built-in terminal app writes "lazarus".
124	122
125	123		3, Open Lazarus. Define a new external tool in the Tools menu, with the program of /bin/sh and the following parameters.
126	124
127	125		``` bash
128	126		-c 'osascript -e "tell application \"Terminal\" to do script \"echo lazarus\""'
129	127		```
130	128
131	129		After you've added the tool, restart Lazarus, and click on it. The same system protection dialog will pop up, but for Lazarus now. Say yes, to allow it.
132	130
133	131		After doing these prerequsities, you can safely tick the "LaunchNewTerminal" option in the global settings, and every time you start a debugging, you can control stdin/stdout of the debugged program in a separate terminal window.
134	132
135	133		Note: Debugging will be really, really, really slow, unless you add the dedicated Debug/Release modes to your project, and use the Debug one for debugging. Use Dwarf2 symbols at the moment when possible.
136	134
137	135		## See also
138	136
139	137		- [[GDB Debugger Tips\|General tips/info on debugging]]
140	138
141	139		---
142	140		From the Free Pascal wiki, page "Debugger Console App", as it stood on 2023-06-18 after a change by Shaglonux, 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).
143	141		Category: Debugging
144	142		Category: Lazarus

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