如何显示gdb以正确显示变量? [英] How can I show gdb to show my variables properly?
问题描述
例如,我有一个简单的子字符串类和一个简单的数组.当我调试时,这很头疼,因为我需要多次单击才能获取某种有意义的信息.有没有一种方法可以标记我的源代码,其中包含某种配置,该配置信息表示当我打印变量a时实际上是我的意思
For example I have a simple substring class and a simple array. When I'm debugging it's a headache because I need many clicks just to get some kind of sensible information. Is there a way I can markup my source of have some kind of config that says when I print the variable a I actually mean
p *a.start@(a.end-a.start)
当我检查数组时,我希望它以上面的样式显示变量( p *arr.array@arr.pos
真是一团糟)
When I exam array I'd like it to show the variable in the style above (p *arr.array@arr.pos
is a mess)
当前GDB输出
$ gdb ./a.out
(gdb) br a.cpp:38
Breakpoint 1 at 0x128f: file a.cpp, line 38.
(gdb) r
(gdb) p a
$1 = {start = 0x555555556004 "My test string that has two parts", end = 0x555555556012 " that has two parts"}
(gdb)
我的Source用 g ++ -g a.cpp
#include <cstdio>
struct MyString
{
const char *start, *end;
int size() { return end-start; }
};
template<class T>
struct MyArray
{
int pos;
T array[10];
MyArray() : pos(0) {}
void push(T val) {
if (pos >= 10)
return;
array[pos++] = val;
}
};
struct MoreComplex
{
int val;
MyString substring;
};
int main() {
const char* str = "My test string that has two parts";
MyString a{str, str+14};
MyString b{str+20, str+27};
MoreComplex c{5, b};
MyArray<MyString> arr;
arr.push(a);
arr.push(b);
MyArray<MoreComplex*> arr2;
arr2.push(&c);
puts("Breakpoint here");
return 0;
}
推荐答案
如果您使用的是基于python的gdb版本,则可以添加自定义
If you have a python-enabled build of gdb, you can add custom pretty printers for your types.
您可以尝试将以下内容添加到.gdbinit中:
You could try adding the following to your .gdbinit:
python
class MyStringPrinter:
"Print a MyString"
def __init__ (self, val):
self.val = val
def to_string (self):
ptr = self.val['start']
len = self.val['end'] - ptr
return ptr.string (length = len)
def display_hint (self):
return 'string'
pp = gdb.printing.RegexpCollectionPrettyPrinter("mine")
pp.add_printer('MyString', '^MyString$', MyStringPrinter)
gdb.printing.register_pretty_printer(gdb.current_objfile(), pp)
end
这将在打印 MyString
对象时为您提供此结果:
This will give you this result when printing a MyString
object:
(gdb) p a
$1 = "My test string"
(gdb) p b
$2 = "has two"
(gdb) p c
$3 = {val = 5, substring = "has two"}
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