end*_*gin 21 c++ gdb stdvector
我有一个std :: vector作为类的一部分,它包含一个自定义类型.它的内容似乎从程序的某个地方神秘地改变了.我无法弄清楚这是怎么回事.
有没有办法从gdb"观察"std :: vector的内容(或大小)？
谢谢.
Emp*_*ian 11
有没有办法从gdb"观察"std :: vector的内容(或大小)？
假设您正在使用GCC,请在theVector->_M_impl._M_start和上设置观察点_M_finish.如果您正在使用其他一些std :: vector实现,请相应地进行调整.
例:
#include <vector>
int main()
{
std::vector<int> v;
v.push_back(1);
v.push_back(2);
}
g++ -g t.cc
gdb -q ./a.out
Reading symbols from /tmp/a.out...done.
(gdb) start
Temporary breakpoint 1 at 0x40090f: file t.cc, line 5.
Temporary breakpoint 1, main () at t.cc:5
5 std::vector<int> v;
(gdb) n
7 v.push_back(1);
(gdb) p v._M_impl._M_start
$1 = (int *) 0x0
(gdb) p v._M_impl._M_finish
$2 = (int *) 0x0
(gdb) p &v._M_impl._M_finish
$3 = (int **) 0x7fffffffd878
(gdb) watch *$3
Hardware watchpoint 2: *$3
(gdb) p &v._M_impl._M_start
$4 = (int **) 0x7fffffffd870
(gdb) watch *$4
Hardware watchpoint 3: *$4
(gdb) c
Hardware watchpoint 3: *$4
Old value = (int *) 0x0
New value = (int *) 0x604010
std::vector<int, std::allocator<int> >::_M_insert_aux (this=0x7fffffffd870, __position=0x0) at /usr/include/c++/4.4/bits/vector.tcc:365
365 this->_M_impl._M_finish = __new_finish;
(gdb) bt
#0 std::vector<int, std::allocator<int> >::_M_insert_aux (this=0x7fffffffd870, __position=0x0) at /usr/include/c++/4.4/bits/vector.tcc:365
#1 0x0000000000400a98 in std::vector<int, std::allocator<int> >::push_back (this=0x7fffffffd870, __x=@0x7fffffffd88c) at /usr/include/c++/4.4/bits/stl_vector.h:741
#2 0x0000000000400935 in main () at t.cc:7
(gdb) c
Hardware watchpoint 2: *$3
Old value = (int *) 0x0
New value = (int *) 0x604014
std::vector<int, std::allocator<int> >::_M_insert_aux (this=0x7fffffffd870, __position=0x0) at /usr/include/c++/4.4/bits/vector.tcc:366
366 this->_M_impl._M_end_of_storage = __new_start + __len;
(gdb) bt
#0 std::vector<int, std::allocator<int> >::_M_insert_aux (this=0x7fffffffd870, __position=0x0) at /usr/include/c++/4.4/bits/vector.tcc:366
#1 0x0000000000400a98 in std::vector<int, std::allocator<int> >::push_back (this=0x7fffffffd870, __x=@0x7fffffffd88c) at /usr/include/c++/4.4/bits/stl_vector.h:741
#2 0x0000000000400935 in main () at t.cc:7
... etc...