TCP sendto (C++) fails on Linux but not OSX. Errno: EINVAL 22 Invalid argument - linux

Question

On the client side of my application, the following runs fine on OSX. But when compiled/run on Linux (Ubuntu 12 or Raspbian) sendto() always fails with a EINVAL/22/invalid argument. How do I run it on Linux?
std::vector<uint8_t> rawVect;
// rawVect.push_back()...a bunch of bytes
const uint8_t* sendBytes = &rawVect[0]; // or rawVect.data();
size_t sendSize = rawVect.size();
if(sendSize > 0){
long numBytes = sendto(control_fd, sendBytes, sendSize, 0, res->ai_addr, _res->ai_addrlen);
}
I suspect C++ 11 libraries and std::vectors on Linux. My makefile looks similar to this.
mac:
g++ -std=c++0x myprogram.cpp
# (w/ llvm libc++)
ubuntu:
clang++-3.5 -g -std=c++11 -stdlib=libc++ myprogram.cpp
# couldn't use g++ 4.8 or prior because it didn't support std::vector::insert as I was using it elsewhere. 4.9 not avail for Ubuntu 12.
pi:
g++-4.9 -std=c++0x myprogram.cpp

Answer 1

man 3 sendto says that EINVAL may be returned if "The dest_len argument is not a valid length for the address family", perhaps despite the fact that the address argument is ignored for connected-mode sockets. Given that you mention TCP in the title, I assume that control_fd is a connected-mode socket. Try simply using send(control_fd, sendBytes, sendSize, 0) or even write(control_fd, sendBytes, SendSize) instead.

Answer 2

There's not enough to go on. Add print statements to reveal the values of all the parameters passed to sendto. Then print out the relevant members of res->ai_addr after casting back to sockaddr_in.
One hypothesis. The value of ai_addrlen should exactly equal sizeof(struct sockaddr_in) assuming ipv4. Or sizeof(sockaddr_in6) if the socket is ipv6. Some operating systems are less forgiving if you pass in a value that's bigger than the actual size expected for that socket type. Such would be the case with assigning the ai_addrlen to be sizeof(sockaddr_storage).