Began work on a DLL for communicating with other processes through sockets.

DLLSocket/DLLSocket.cbp

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+<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>
+<CodeBlocks_project_file>
+	<FileVersion major="1" minor="6" />
+	<Project>
+		<Option title="DLLSocket" />
+		<Option pch_mode="2" />
+		<Option compiler="gcc" />
+		<Build>
+			<Target title="Debug">
+				<Option output="bin\Debug\DLLSocket" prefix_auto="1" extension_auto="1" />
+				<Option object_output="obj\Debug\" />
+				<Option type="3" />
+				<Option compiler="gcc" />
+				<Option createDefFile="1" />
+				<Option createStaticLib="1" />
+				<Compiler>
+					<Add option="-Wall" />
+					<Add option="-DBUILD_DLL" />
+					<Add option="-g" />
+				</Compiler>
+				<Linker>
+					<Add library="user32" />
+				</Linker>
+			</Target>
+			<Target title="Release">
+				<Option output="bin\Release\DLLSocket" prefix_auto="1" extension_auto="1" />
+				<Option object_output="obj\Release\" />
+				<Option type="3" />
+				<Option compiler="gcc" />
+				<Option createDefFile="1" />
+				<Option createStaticLib="1" />
+				<Compiler>
+					<Add option="-Wall" />
+					<Add option="-DBUILD_DLL" />
+					<Add option="-O2" />
+				</Compiler>
+				<Linker>
+					<Add option="-s" />
+					<Add library="user32" />
+				</Linker>
+			</Target>
+		</Build>
+		<Unit filename="main.cpp" />
+		<Unit filename="main.h" />
+		<Extensions>
+			<code_completion />
+			<debugger />
+		</Extensions>
+	</Project>
+</CodeBlocks_project_file>

DLLSocket/main.cpp

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+// OS-specific networking includes
+// -------------------------------
+#ifdef __WIN32
+    #include <winsock2.h>
+    typedef int socklen_t;
+#else
+    extern "C" {
+    #include <sys/types.h>
+    #include <sys/socket.h>
+    #include <netinet/in.h>
+    #include <arpa/inet.h>
+    #include <netdb.h>
+    #include <fcntl.h>
+    }
+
+    typedef int SOCKET;
+    typedef sockaddr_in SOCKADDR_IN;
+    typedef sockaddr SOCKADDR;
+    #define SOCKET_ERROR -1
+#endif
+
+// Socket used for all communications
+SOCKET sock;
+
+// Address of the remote server
+SOCKADDR_IN addr;
+
+// Buffer used to return dynamic strings to the caller
+#define BUFFER_SIZE 1024
+char return_buffer[BUFFER_SIZE];
+
+// exposed functions
+// ------------------------------
+
+const char* SUCCESS = "1\0"; // string representing success
+
+// arg1: ip(in the xx.xx.xx.xx format)
+// arg2: port(a short)
+// return: NULL on failure, SUCCESS otherwise
+extern "C" const char* establish_connection(int n, char *v[])
+{
+    // extract args
+    // ------------
+    if(n < 2) return 0;
+    const char* ip = v[0];
+    const char* port_s = v[1];
+    unsigned short port = atoi(port_s);
+
+    // set up network stuff
+    // --------------------
+    #ifdef __WIN32
+        WSADATA wsa;
+        WSAStartup(MAKEWORD(2,0),&wsa);
+    #endif
+    sock = socket(AF_INET,SOCK_DGRAM,0);
+
+    // make the socket non-blocking
+    // ----------------------------
+    #ifdef __WIN32
+        unsigned long iMode=1;
+        ioctlsocket(sock,FIONBIO,&iMode);
+    #else
+        fcntl(sock, F_SETFL, O_NONBLOCK);
+    #endif
+
+    // establish a connection to the server
+    // ------------------------------------
+    memset(&addr,0,sizeof(SOCKADDR_IN));
+    addr.sin_family=AF_INET;
+    addr.sin_port=htons(port);
+
+    // convert the string representation of the ip to a byte representation
+    addr.sin_addr.s_addr=inet_addr(ip);
+
+    return SUCCESS;
+}
+
+// arg1: string message to send
+// return: NULL on failure, SUCCESS otherwise
+extern "C" const char* send_message(int n, char *v[])
+{
+    // extract the args
+    const char* msg = v[1];
+
+    // send the message
+    int rc = sendto(sock,msg,strlen(msg),0,(SOCKADDR*)&addr,sizeof(SOCKADDR));
+
+    // check for errors
+    if (rc != -1) {
+       return SUCCESS;
+    }
+    else {
+       return 0;
+    }
+}
+
+// no args
+// return: message if any received, NULL otherwise
+extern "C" const char* recv_message(int n, char *v[])
+{
+    SOCKADDR_IN sender; // we will store the sender address here
+
+    socklen_t sender_byte_length = sizeof(sender);
+
+    // Try receiving messages until we receive one that's valid, or there are no more messages
+    while(1) {
+        int rc = recvfrom(sock, return_buffer, BUFFER_SIZE,0,(SOCKADDR*) &sender,&sender_byte_length);
+        if(rc > 0) {
+            // we could read something
+
+            if(sender.sin_addr.s_addr != addr.sin_addr.s_addr) {
+                continue; // not our connection, ignore and try again
+            } else {
+                return_buffer[rc] = '0'; // 0-terminate the string
+                return return_buffer;
+            }
+        }
+        else {
+            break; // no more messages, stop trying to receive
+        }
+    }
+
+    return 0;
+}