GNU gdb (GDB) 8.1
Copyright (C) 2018 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later
This is free software: you are free to change and redistribute it.
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:
.
Find the GDB manual and other documentation resources online at:
.
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
...
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/libc.so.6
#1 0x7f59df6c8c7c in ?? () from /usr/lib/libglib-2.0.so.0
#2 0x7f59df6c8d8c in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#3 0x7f59e480b23f in QEventDispatcherGlib::processEvents(...)
from /usr/lib/libQt5Core.so.5
...
(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 =
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()
42
(gdb) ptype MyType
type = class MyType {
private:
int foo;
public:
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
1.1 y 0x7ffff6f143f0
...
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/libc.so.6
* 1 Thread 0x7ffff7edd840 (LWP 7267) \"kwrite\"
0x7ffff0b6718d in poll () from /usr/lib/libc.so.6
(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/ld-linux-x86-64.so.2
0x7ffff7690460 0x7ffff7ab723c Yes /opt/qt/5.5/gcc_64/lib/libQt5Gui.so.5
0x7ffff6efdb80 0x7ffff71af318 Yes /opt/qt/5.5/gcc_64/lib/libQt5Core.so.5
0x7ffff6c02f60 0x7ffff6c5f852 Yes (*) /usr/lib/libGL.so.1
0x7ffff69d3ac0 0x7ffff69e0931 Yes (*) /usr/lib/libpthread.so.0
0x7ffff66d5fa0 0x7ffff6781d89 Yes /usr/lib/libstdc++.so.6
0x7ffff6353510 0x7ffff63bb33a Yes (*) /usr/lib/libm.so.6
...
(*): 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();
64
65 QPainter painter(this);
66 painter.setRenderHint(QPainter::Antialiasing);
67 painter.fillRect(rect, Qt::black);
68
(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
Continuing.
paint rect(w=202,h=200)
paint rect(w=213,h=203)
(gdb) target remote :
Remote debugging using :
Reading /lib64/ld-linux-x86-64.so.2 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 = {
[\"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