c++ - gdb: 打印 sockaddr 指针值

Question

目前我正在尝试部署一个用C++编写的网络应用程序，由于网络问题，它看起来陷入了死循环:

[isaev@feck-5 ~]$ sudo strace -p 26252 -f -e trace=network -s 10000 
[pid 26272] getpeername(30, 0x7f1699ddfb60, [28]) = -1 ENOTCONN (Transport endpoint is not connected)
[pid 26272] getpeername(30, 0x7f1699ddfb60, [28]) = -1 ENOTCONN (Transport endpoint is not connected)
[pid 26272] getpeername(30, 0x7f1699ddfb60, [28]) = -1 ENOTCONN (Transport endpoint is not connected)
[pid 26272] getpeername(30, 0x7f1699ddfb60, [28]) = -1 ENOTCONN (Transport endpoint is not connected)
[pid 26272] getpeername(30, 0x7f1699ddfb60, [28]) = -1 ENOTCONN (Transport endpoint is not connected)
[pid 26272] getpeername(30, 0x7f1699ddfb60, [28]) = -1 ENOTCONN (Transport endpoint is not connected)
[pid 26272] getpeername(30, 0x7f1699ddfb60, [28]) = -1 ENOTCONN (Transport endpoint is not connected)

我需要知道应用程序缺少哪个网络连接。

假设我可以使用 gdb 附加到进程，我如何打印 truct sockaddr * ( man getpeername ) 变量的值 0x7f1699ddfb60 指向?

Answer 1

您可以通过执行以下操作“向下转换”和取消引用指针(或其值)

(gdb) p *((struct sockaddr_in_or_whichever_you_use *) pointer_to_struct_sockaddr)

或

(gdb) p *((struct sockaddr_in_or_whichever_you_use *) 0x7f1699ddfb60)