Socket fails to bind (C with WinSock) - c

Question

This is supposed to bind a socket to a port on the local host and accept TCP connections. When I run it, I get my "Bind error" message. I used this tutorial (see the "Accept connection" section), and the only significant difference I can see between that and my code is the position of the server address and port member initializations, which shouldn't matter, as long as they come before the bind() call?
I added a new rule in Windows Firewall (on Windows 7) to allow TCP connections from this executable, on port 8888, but that doesn't seem to help.
#include <stdio.h>
#include <winsock2.h>
#pragma comment(lib, "ws2_32.lib")
int main(int argc, char *argv[])
{
WSADATA wsa;
SOCKET s, new_socket;
struct sockaddr_in server, client;
int c;
printf("\nInitializing WinSock...");
if (WSAStartup(MAKEWORD(2,2),&wsa) != 0)
{
printf("Failed. Error code: %d\n\n", WSAGetLastError());
exit(1);
}
printf("\nInitialized.");
server.sin_addr.s_addr = INADDR_ANY;
server.sin_port = htons(8888);
server.sin_family = AF_INET;
if (s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP) == INVALID_SOCKET)
{
printf("\nCould not create socket: %d", WSAGetLastError());
exit(1);
}
printf("\nSocket created.\n");
if (bind(s, (struct sockaddr *)&server, sizeof(server)) == SOCKET_ERROR)
{
printf("\nBind error.\n\n");
exit(1);
}
printf("\nSocket bound to port 8888.\n\n");
listen(s, 3);
printf("\nWaiting for incoming connections...");
c = sizeof(struct sockaddr_in);
new_socket = accept(s, (struct sockaddr *)&client, &c);
if (new_socket == INVALID_SOCKET)
{
printf("\nAccept failed.\n\n");
exit(1);
}
printf("\nConnection accepted.");
closesocket(s);
WSACleanup();
return 0;
}

Answer 1

This statement:
if (s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP) == INVALID_SOCKET)
Needs an additional set of parenthesis around the assignment:
if ((s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) == INVALID_SOCKET)
The == operator has a higher precedence then the = operator (see Operator Precedence), so your original statement implicitly acts as if you had written it like this instead:
if (s = (socket(AF_INET, SOCK_STREAM, IPPROTO_TCP) == INVALID_SOCKET))
If socket() succeeds, the comparison would evaluate to false, which then assigns 0 to s (since SOCKET is just an alias for UINT_PTR, assigning a boolean value to a SOCKET variable is allowed), and then bind() would fail with the WSAENOTSOCK error (if socket() fails, the comparison would evaluate to true, which would assign 1 to s, then the if would evaluate as true and your process would exit).
Personally, I dislike code that does assignments and comparisons in the same statement. This would be clearer and safer:
s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (s == INVALID_SOCKET)
Also, don't forget to call closesocket() on new_socket after accept() succeeds.