Use enums for tri-state return values

Resolves #112

Author: andy5995

include/SDL3_net/SDL_net.h

@@ -61,6 +61,11 @@ extern "C" {
      (SDL_NET_MAJOR_VERSION > X || SDL_NET_MINOR_VERSION >= Y) && \
      (SDL_NET_MAJOR_VERSION > X || SDL_NET_MINOR_VERSION > Y || SDL_NET_MICRO_VERSION >= Z))
 
+enum NET_TriState {
+    NET_FAILURE = -1,
+    NET_WOULDBLOCK,
+    NET_SUCCESS,
+};
 
 /**
  * This function gets the version of the dynamically linked SDL_net library.

src/SDL_net.c

@@ -214,7 +214,7 @@ static bool SetGetAddrInfoErrorBool(const char *msg, int err)
 }
 
 // this blocks!
-static int ResolveAddress(NET_Address *addr)
+static enum NET_TriState ResolveAddress(NET_Address *addr)
 {
     SDL_assert(addr != NULL);  // we control all this, so this shouldn't happen.
     struct addrinfo *ainfo = NULL;
@@ -225,23 +225,23 @@ static int ResolveAddress(NET_Address *addr)
     //SDL_Log("rc=%d", rc);
     if (rc != 0) {
         addr->errstr = CreateGetAddrInfoErrorString(rc);
-        return -1;  // error
+        return NET_FAILURE;  // error
     } else if (ainfo == NULL) {
         addr->errstr = SDL_strdup("Unknown error (query succeeded but result was NULL!)");
-        return -1;
+        return NET_FAILURE;
     }
 
     char buf[128];
     rc = getnameinfo(ainfo->ai_addr, ainfo->ai_addrlen, buf, sizeof (buf), NULL, 0, NI_NUMERICHOST);
     if (rc != 0) {
         addr->errstr = CreateGetAddrInfoErrorString(rc);
         freeaddrinfo(ainfo);
-        return -1;  // error
+        return NET_FAILURE;  // error
     }
 
     addr->human_readable = SDL_strdup(buf);
     addr->ainfo = ainfo;
-    return 1;  // success (zero means "still in progress").
+    return NET_SUCCESS;  // success (zero means "still in progress").
 }
 
 static int SDLCALL ResolverThread(void *data)
@@ -1335,11 +1335,11 @@ NET_DatagramSocket *NET_CreateDatagramSocket(NET_Address *addr, Uint16 port)
     return sock;
 }
 
-static int SendOneDatagram(NET_DatagramSocket *sock, NET_Address *addr, Uint16 port, const void *buf, int buflen)
+static enum NET_TriState SendOneDatagram(NET_DatagramSocket *sock, NET_Address *addr, Uint16 port, const void *buf, int buflen)
 {
     struct addrinfo *addrwithport = MakeAddrInfoWithPort(addr, SOCK_DGRAM, port);
     if (!addrwithport) {
-        return -1;
+        return NET_FAILURE;
     }
     const int rc = sendto(sock->handle, buf, (size_t) buflen, 0, addrwithport->ai_addr, addrwithport->ai_addrlen);
     freeaddrinfo(addrwithport);
@@ -1350,15 +1350,15 @@ static int SendOneDatagram(NET_DatagramSocket *sock, NET_Address *addr, Uint16 p
     }
 
     SDL_assert(rc == buflen);
-    return 1;
+    return NET_SUCCESS;
 }
 
 // see if any pending data can finally be sent, etc
 static int PumpDatagramSocket(NET_DatagramSocket *sock)
 {
     if (!sock) {
         SDL_InvalidParamError("sock");
-        return -1;
+        return NET_FAILURE;
     }
 
     while (sock->pending_output_len > 0) {
@@ -1367,7 +1367,7 @@ static int PumpDatagramSocket(NET_DatagramSocket *sock)
         const int rc = SendOneDatagram(sock, dgram->addr, dgram->port, dgram->buf, dgram->buflen);
         if (rc < 0) {  // failure!
             return -1;
-        } else if (rc == 0) {  // wouldblock
+        } else if (rc == NET_WOULDBLOCK) {
             break;  // stop trying to send packets for now.
         }