How can I cast a socket to an SSLConnectionRef without getting a warning?

I'm learning how to use Apple's Secure Transport framework to implement TLS for my networking, and it's a bit confusing. I believe I'm supposed to just cast my socket fds to SSLConnectionRefs, but I get a warning when I do so Cast to 'SSLConnectionRef' (aka 'const void *') from smaller integer type 'int'.

int sockfd = socket(...);
...
SSLContextRef sslContext = SSLCreateContext(...);

// This line gives the warning
SSLSetConnection(sslContext, (SSLConnectionRef)sockfd);

I'm not losing any information here, since void * is larger than int, right? So this should be safe. I'm just concerned by the compiler warning. Thanks for any suggestions.

Solution

(SSLConnectionRef)(long)sockfd works and should be safe as long as sizeof(void*) > sizeof(int) which is true for all current compilers, but not necessarily guaranteed.

Another approach would be to temporarily disable the warning:

#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wint-to-point-cast"
    SSLSetConnection(sslContext, (SSLConnectionRef)sockfd);
#pragma clang diagnostic pop

Ultimately, the "right" solution would be to actually pass in a pointer to an integer that you allocate via malloc or some other scheme. If this is all in an object, store the fd in an instance variable and pass in &_sockfd;