C++ - Initializing SOCKADDR_IN

c++ initialization winsock
DukeOfMarmalade picture DukeOfMarmalade · Jun 6, 2012 · Viewed 10.2k times · Source

I am working through some Static Analysis defects and one that is causing me an issue is this one. 

SOCKADDR_IN m_stLclAddr;

SOCKADDR_IN is a member of the WinSock API

The defect is saying that I have not initialized the following:

  • m_stLclAddr.sin_port
  • m_stLclAddr.sin_zero
  • m_stLclAddr.sin_addr
  • m_stLclAddr.sin_family

I am not very familiar familiar with the WinSock API but I have done a bit of research and I just want to know if the following line of code would initialize m_stLclAddr with default values?:

m_stLclAddr = { 0 };

Answer

bn. picture bn. · Jun 6, 2012

m_stLclAddr = {0} will set everything to zero the first time (not necessarily default values or what you actually want to do). memset(&m_stLclAddr, 0, sizeof(SOCKADDR_IN)); will set everything in m_stLclAddr to zero for not only initialization, but successive calls as well.

I would think you would want to do something like this:

local_sin.sin_family = AF_INET;
local_sin.sin_port = htons (PORTNUM);
local_sin.sin_addr.s_addr = htonl (INADDR_ANY);

as shown here: http://msdn.microsoft.com/en-us/library/aa454002.aspx

Related questions

What is the easiest way to initialize a std::vector with hardcoded elements?

I can create an array and initialize it like this: int a[] = {10, 20, 30}; How do I create a std::vector and initialize it similarly elegant? The best way I know is: std::vector<int> ints; ints.push_back(10); ints.…

Read More
How to initialize private static members in C++?

What is the best way to initialize a private, static data member in C++? I tried this in my header file, but it gives me weird linker errors: class foo { private: static int i; }; int foo::i = 0; I'm guessing this …

Read More
Initialization of all elements of an array to one default value in C++?

C++ Notes: Array Initialization has a nice list over initialization of arrays. I have a int array[100] = {-1}; expecting it to be full with -1's but its not, only first value is and the rest are 0's mixed with …

Read More