GNU gdb (GDB) 8.1
Copyright (C) 2018 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <>
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There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-pc-linux-gnu".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
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For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from your_application...done.
(gdb) break main
# this is a comment
(gdb) run <arguments for your application>
Breakpoint 1 at 0x400b56: file yourmain.cpp, line 3
3: int main(int argc, char* argv[])
(gdb) continue
(gdb) backtrace
#0  0x7f59e39bf18d in poll () from /usr/lib/
#1  0x7f59df6c8c7c in ?? () from /usr/lib/
#2  0x7f59df6c8d8c in g_main_context_iteration () from /usr/lib/
#3  0x7f59e480b23f in QEventDispatcherGlib::processEvents(...)
    from /usr/lib/
(gdb) where
#0  main (argc=1, argv=0x7fffffffca88) at ../../debugging/ex_debugger/main.cpp:11
(gdb) list
10          bool run = true;
11          while (run) {
12              // infinite loop! can you make it quit?
13          }
(gdb) info locals
app = <incomplete type>
run = true
complexData = {{d = 0x61d430, e = 0x61d430}}
(gdb) info scope main.cpp:12
Scope for main.cpp:12:
Symbol argc is a variable at frame base reg $rbp offset 0+-8, length 4.
Symbol argv is a variable at frame base reg $rbp offset 0+-16, length 8.
(gdb) ptype run
type = bool
(gdb) print run
run = true
(gdb) set run = false
(gdb) print run
run = false
(gdb) print myString.size()
(gdb) ptype MyType
type = class MyType {
    int foo;
    int foo() const;
(gdb) break QMessageLogger::warning
Breakpoint 1 at 0x7ffff6f143f0 (8 locations)
(gdb) command 1
Type commands for breakpoint(s) 1, one per line.
End with a line saying just \"end\".
> backtrace
> continue
> end
(gdb) catch throw # or when an exception is thrown
Catchpoint 2 (throw)
(gdb) break main.cpp:12 # or when certain code is executed
Breakpoint 3 at 0x401216: file ../../debugging/ex_debugger/main.cpp, line 12.
(gdb) info breakpoints
Num     Type           Disp Enb Address            What
1       breakpoint     keep y   <MULTIPLE>
1.1                         y     0x7ffff6f143f0 <QMessageLogger::warning(char const*, …
2       breakpoint     keep y   0x7ffff66d9b90 exception throw
3       breakpoint     keep y   0x000000401216 in main(int, char**)
                                                at debugging/ex_debugger/main.cpp:12
(gdb) condition 3 argc > 5
                # ^-- breakpoint id, see `info breakpoints` above
(gdb) call myFunction()
(gdb) set pagination off
(gdb) set logging file /tmp/warnings.log
(gdb) set logging on
Copying output to /tmp/warnings.log.
(gdb) info threads
            Id   Target Id         Frame
2    Thread 0x7fffe10e1700 (LWP 7271) \"QXcbEventReader\"
    0x7ffff0b6718d in poll () from /usr/lib/
* 1    Thread 0x7ffff7edd840 (LWP 7267) \"kwrite\"
    0x7ffff0b6718d in poll () from /usr/lib/
(gdb) thread
[Current thread is 1 (Thread 0x7ffff7edd840 (LWP 7267))]
(gdb) thread 2
[Switching to thread 2 (Thread 0x7fffe10e1700 (LWP 9765))]
(gdb) thread apply all backtrace
(gdb) info sharedlibrary
From                To                  Syms Read   Shared Object Library
0x7ffff7ddbb80  0x7ffff7df5610  Yes (*)     /lib64/
0x7ffff7690460  0x7ffff7ab723c  Yes         /opt/qt/5.5/gcc_64/lib/
0x7ffff6efdb80  0x7ffff71af318  Yes         /opt/qt/5.5/gcc_64/lib/
0x7ffff6c02f60  0x7ffff6c5f852  Yes (*)     /usr/lib/
0x7ffff69d3ac0  0x7ffff69e0931  Yes (*)     /usr/lib/
0x7ffff66d5fa0  0x7ffff6781d89  Yes         /usr/lib/
0x7ffff6353510  0x7ffff63bb33a  Yes (*)     /usr/lib/
(*): Shared library is missing debugging information.
(gdb) list 64
59           * If no red can be seen, then the cached implementation is \"good enough\".
60           */
61          void paintEvent(QPaintEvent *event)
62          {
63              const QRect rect = event->rect();
65              QPainter painter(this);
66              painter.setRenderHint(QPainter::Antialiasing);
67              painter.fillRect(rect, Qt::black);
(gdb) dprintf main.cpp:64,\"paint rect(w=%d,h=%d)\\n\",rect.width(),rect.height()
Dprintf 1 at 0x403a1e: file path/to/main.cpp, line 64.
(gdb) continue
paint rect(w=202,h=200)
paint rect(w=213,h=203)
(gdb) target remote <device ip>:<port>
Remote debugging using <device ip>:<port>
Reading /lib64/ from remote target...
warning: File transfers from remote targets can be slow.
            Use \"set sysroot\"to access files locally instead.
(gdb) set sysroot /path/to/sysroot
(gdb) print myMap
$1 = QMap<QString, int> = {
    [\"bar\"] = 1,
    [\"foo\"] = 2
(gdb) print money
$1 {
    {value = 1.20000005, currency = Money::Euro},
    {value = 3.4000001, currency = Money::Dollar}
(gdb) python
> import sys
> sys.path.insert(0, '/path/to/addon/debugging/ex_gdb_pretty_printer')
> import money_printer
> end
(gdb) print money
$2 = {
    \"1.200000 Euro\",
    \"3.400000 Dollar\"
(gdb) continue
(gdb) detach
(gdb) quit