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cgetaddrinfo

Is struct addrinfo **res allocated when getaddrinfo() returns a non-zero value?

I am having some memory leaking troubles in an embedded application and while looking in the code, I see I do not freeaddrinfo() when getaddrinfo() returns non-zero:

s = getaddrinfo(hostname, port, &hints, &result);
if (s != 0) {
  log_error();
} else {
  // do stuff
  freeaddrinfo(result);
}

Could this lead to memory leaks? I have tried to look into the man page, but it doesn't state it explicitly.

Solution

  • The specification doesn't say that result isn't assigned if it fails, so it appears that a conforming implementation could do so.

    Why not free it unconditionally?

    result = 0;
s = getaddrinfo(hostname, port, &hints, &result);
if (s) {
    // log error
} else {
    // success
}
if (result) {
    freeaddrinfo(result);
}

    Ideally you'd be able to call freeaddrinfo(result) without checking whether result is NULL, but although it's implied by the standard that that's OK I wouldn't count on it.