我的发行版（Debian）将调试文件发送到单独的包中。所以经常发生的事情是我在#include <stdio.h>
#include <conio.h>
#include <iostream>
using namespace std;
class point
{
private:
int x,y;
public:
point(int ox =0, int oy =0)
{
cout << " Make object" << this << endl;
cout << " Using default constructor \n";
x = ox, y = oy;
}
point(const point &p)
{
cout << " Make object" << this << endl;
cout << " Using copy constructor \n";
x = p.x, y = p.y;
}
void move(int dx, int dy);
void display();
};
point fct(point a);
int main()
{
point a(5,2);
a.display();
point b = fct (a);
b.display();
getch();
return 0;
}
void point::move(int dx, int dy)
{
x += dx, y += dy;
}
void point::display()
{
cout << "Coordinates :" << x << " " << y << "\n";
}
point fct(point a)
{
point b=a;
//b.move(2,3);
return b;
}
中运行一个程序直到它崩溃，以获得错误报告的可用回溯。但gdb相当无用，缺少符号信息 - 因为我没有安装相应的bt包。
如果我现在安装软件包，有没有办法让-dbg再次搜索符号文件，而不会丢失我当前的回溯？
答案 0 :(得分：4)
有一个技巧可以让gdb再次尝试读取符号文件：
(gdb) nosharedlibrary
(gdb) sharedlibrary
第一个命令告诉它忘记它拥有的所有符号信息，第二个命令告诉它重新读取它。
答案 1 :(得分：1)
我将建议使用gdb using System;
using System.IO;
using System.Linq;
namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
var buffer = new byte[1024];
int pos = 0;
using (var fileIn = new FileStream(@"c:\test.txt", FileMode.Open, FileAccess.Read))
using (var fileOut = new FileStream(@"c:\test.txt.binary", FileMode.Create, FileAccess.Write))
while((pos = fileIn.Read(buffer,0,buffer.Length)) > 0)
foreach (var value in buffer.Take(pos).Select(x => Convert.ToString(x, 2).PadLeft(8, '0')))
fileOut.Write(value.Select(x => (byte)x).ToArray(), 0, 8);
}
}
}
命令的替代方法，可能它适合您。
这是gcore描述：
gcore所以我有一个导致崩溃的程序：
(gdb) help gcore
Save a core file with the current state of the debugged process.
Argument is optional filename. Default filename is 'core.<process_id>'
我用调试信息编译了它。但是，我将带有调试信息的可执行文件放在存档中，并且测试使用剥离版本。
所以它在gdb下崩溃了：
include <iostream>
int f()
{
time_t curr_ts = time(0);
std::cout << "Before crash " << curr_ts << std::endl;
int * ptr = 0;
*ptr = *ptr +1 ;
std::cout << "After crash " << curr_ts << std::endl;
return *ptr;
}
int main()
{
std::cout << "Before f() " << std::endl;
f();
std::cout << "After f() " << std::endl;
return 0;
}
我只使用$ gdb ./a.out
Reading symbols from ./a.out...(no debugging symbols found)...done.
(gdb) r
Starting program: /home/crash/a.out
Before f()
Before crash 1435322344
Program received signal SIGSEGV, Segmentation fault.
0x000000000040097d in ?? ()
(gdb) bt
#0 0x000000000040097d in ?? ()
#1 0x00000000004009e0 in ?? ()
#2 0x000000314981ed1d in __libc_start_main () from /lib64/libc.so.6
#3 0x00000000004007f9 in ?? ()
#4 0x00007fffffffde58 in ?? ()
#5 0x000000000000001c in ?? ()
#6 0x0000000000000001 in ?? ()
#7 0x00007fffffffe1a9 in ?? ()
#8 0x0000000000000000 in ?? ()
(gdb) gcore crash2.core
Saved corefile crash2.core
生成核心文件并保留gdb。然后我从存档中获得带有调试符号的版本，我可以看到所有符号：
gcore更新
如果您$ gdb ./a.out ./crash2.core
Reading symbols from ./a.out...done.
warning: exec file is newer than core file.
[New LWP 15215]
Core was generated by `/home/crash/a.out'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0 0x000000000040097d in f () at main.cpp:8
8 *ptr = *ptr +1 ;
(gdb) bt
#0 0x000000000040097d in f () at main.cpp:8
#1 0x00000000004009e0 in main () at main.cpp:17
(gdb) info locals
curr_ts = 1435322344
ptr = 0x0
，您至少会看到此set backtrace past-main on。如果您只分析核心文件（可能甚至没有保存在那里）保存机智__libc_start_main，则不会打印上面__libc_start_main以上的内容：
gcore但如果我使用我的测试程序（包含调试信息）重现$ gdb ./a.out crash2.core
Reading symbols from ./a.out...done.
warning: exec file is newer than core file.
[New LWP 15215]
Core was generated by `/home/crash/a.out'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0 0x000000000040097d in f () at main.cpp:8
8 *ptr = *ptr +1 ;
(gdb) set backtrace past-main on
(gdb) bt
#0 0x000000000040097d in f () at main.cpp:8
#1 0x00000000004009e0 in main () at main.cpp:17
#2 0x000000314981ed1d in __libc_start_main () from /lib64/libc.so.6
Backtrace stopped: Cannot access memory at address 0x4007d0
(gdb)
下的崩溃，我可以看到所有内容（请参阅gdb＆amp;＆amp; set backtrace past-main on）：
set backtrace past-entry on