gdb调用函数 - 如何使用std :: cout作为参数? [英] gdb call function - how to use std::cout as parameter?
问题描述
我有以下代码:
#include< iostream>
使用namespace std;
命名空间ns
{
class D
{
int n;
public:
D(int _n):n(_n){}
void dump(ostream& os);
};
};
void
ns :: D :: dump(ostream& os)
{
os<< n =<< n<<的std :: ENDL;
int main(){
ns :: D d(200);
返回0;
在GDB中,当我发出命令时,调用d.dump(std :: cout)
,在行 return 0;
,我得到这个gdb错误:
表达式中的语法错误,靠近`cout)'。
任何建议如何在gdb调用函数中传递std :: cout?
[更新]
实际上是因为gdb,我使用7.2;在我切换到7.11.1后,它工作正常。
我使用的是:
GNU gdb(Ubuntu 7.11.1-0ubuntu1〜16.04)7.11.1
我很快意识到,调试器完全没有看到 std :: cout
符号,可能是因为它没有在你的代码中使用。所以我改变了主函数,如下所示:
pre $ int main(){
std :: cout<< 你好,世界! <<的std :: ENDL;
ns :: D d(200);
返回0;
}
现在当我运行调试器时,我可以执行您的调用而不会出现问题:
(gdb)break main
断点1在0x400955:文件main.cpp,第24行。
(gdb)运行
启动程序:gdb_cout / main
main.cpp中的main():24
24 main(){
gdb)next
25 std :: cout<< 你好,世界! <<的std :: ENDL;
(gdb)下一个
Hello world!
26 ns :: D d(200);
(gdb)next
27 return 0;
(gdb)调用d.dump(std :: cout)
n = 200
(gdb)
I have the following code:
#include <iostream>
using namespace std;
namespace ns
{
class D
{
int n;
public:
D(int _n):n(_n){}
void dump(ostream &os);
};
};
void
ns::D::dump(ostream &os)
{
os << "n=" << n << std::endl;
}
int main() {
ns::D d(200);
return 0;
}
In GDB, when I issue the command, call d.dump(std::cout)
, at the line return 0;
, I get this gdb error:
A syntax error in expression, near `cout)'.
Any suggestion how I can pass "std::cout" in gdb calling function?
[UPDATE] Actually it is because of gdb, I was using 7.2; after I switch to 7.11.1, it works fine.
I am using:
GNU gdb (Ubuntu 7.11.1-0ubuntu1~16.04) 7.11.1
I soon realized, that the debugger does not see std::cout
symbol at all, probably because it is not used in your code. So I changed the main function as follows:
int main() {
std::cout << "Hello world!" << std::endl;
ns::D d(200);
return 0;
}
And now when I run the debugger, I can perform your call without a problem:
(gdb) break main
Breakpoint 1 at 0x400955: file main.cpp, line 24.
(gdb) run
Starting program: gdb_cout/main
Breakpoint 1, main () at main.cpp:24
24 int main() {
(gdb) next
25 std::cout << "Hello world!" << std::endl;
(gdb) next
Hello world!
26 ns::D d(200);
(gdb) next
27 return 0;
(gdb) call d.dump(std::cout)
n=200
(gdb)
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