added multiple-connection functions

README

@@ -44,6 +44,29 @@ This function tries to connect to a server at <hostname>, _already listening_ on
 		return 0;
 	}
 
+To write a server that accepts multiple connections, do like this:
+
+	#include "tcpconnect.h"
+
+	int main(int argc, char **argv) {
+		int sockfd = tcpconnect_start_multiple(argv[1]); /* ./server 5555 */
+		int acceptsock = 0;
+		while (1) {
+			acceptsock = tcpconnect_accept_single(sockfd);
+			/* create a new thread or fork() and pass the new thread/process
+			   the returned file descriptor
+			   Example:
+			   pthread_t tid;
+			   int *sockptr = malloc(sizeof (int));
+			   *sockptr = accpetsock;
+			   pthread_create(&tid, NULL, server_thread_function, sockptr);
+			*/ 
+		}
+		return 0;
+	}
+
+
+
 An asynchronously working wrapper Objective-C class, TCPHelper is built around these functions. It uses a delegation system to notify
 about its state changes, corresponding to certain network actions. The method names of this class are meant to be self-explanatory, so I've included some example code in Server.m and Client.m. (You can build them using `make sample'.)
 

tcpconnect.c

@@ -49,7 +49,7 @@ int tcpconnect_start_client(const char *hostname, const char *port) {
 	return sockfd;
 }
 
-int tcpconnect_start_server(const char *port) {
+int tcpconnect_start_multiple(const char *port) {
 	int status = 0; /* return status of the inet/socket functions */
 	struct addrinfo *servinfo = NULL;
 	struct addrinfo hints;
@@ -102,14 +102,28 @@ int tcpconnect_start_server(const char *port) {
 		return -1;
 	}
 
+	return sockfd;
+}
+
+int tcpconnect_accept_single(int stubfd) {
 	struct sockaddr_storage client_addr; /* client's address info */
 	socklen_t clientaddr_size = sizeof(client_addr);
-	int newsockfd = accept(sockfd, (struct sockaddr *)&client_addr, &clientaddr_size);
-	close(sockfd);
+	int newsockfd = accept(stubfd, (struct sockaddr *)&client_addr, &clientaddr_size);
 	if (newsockfd < 0) {
 		return -1;
 	}
-
 	return newsockfd;
 }
 
+int tcpconnect_start_server(const char *port) {
+	int stubfd = tcpconnect_start_multiple(port);
+	if (stubfd < 0) {
+		return -1;
+	}
+	int sockfd = tcpconnect_accept_single(stubfd);
+	close(stubfd);
+	if (sockfd < 0) {
+		return -1;
+	}
+	return sockfd;
+}

tcpconnect.h

@@ -18,6 +18,27 @@
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <netdb.h>
+#include <pthread.h>
+
+
+/*
+  Function type to be invoked in separate threads whenever tcpconnect_persistent_server() encounters
+  a new incoming connection. It will be supplied
+  a pointer to a socket file descriptor.
+  This pointer is to be free()'d after use.
+*/
+
+typedef void (*tcpconnect_server_fn_t)(int *fdptr);
+
+/*
+  Callback function used by tcpconnect_persistent_server() to notify about creation of new server threads.
+  This function must not perform heavy computation or otherwise time consuming operations.
+  tid is a pthread_t containing info about the newly spawned thread.
+  sockfd must not be read from nor written to, it's there only in order the callback to know
+  which socket descriptor belongs to which thread.
+*/
+
+typedef void (*tcpconnect_callback_fn_t)(pthread_t tid, int sockfd);
 
 /*
   Returns a socket file descriptor,
@@ -43,5 +64,20 @@ int tcpconnect_start_client(const char *hostname, const char *port);
 
 int tcpconnect_start_server(const char *port);
 
+/*
+  Returns a file descriptor, which can be supplied to tcpconnect_accept_single in order to retrieve
+  a read()able-write()able socket file descriptor.
+*/
+
+int tcpconnect_start_multiple(const char *port);
+
+/*
+  Takes a socket file descriptor returned by tcpconnect_start_multiple(). This blocks until a
+  client connects to the other end of the socket.
+  Returns a readable-writable socket file descriptor on success or negative on error.
+*/
+
+int tcpconnect_accept_single(int stubfd);
+
 #endif /* !__TCPCONNECT_H__ */