v1.7.0 release

examples/01-hello_server.c

@@ -13,7 +13,7 @@ int main(void)
 
     SockAddr addr = sock_addr("0.0.0.0", 6969);
     if (!sock_bind(server, addr)) { err = "bind"; goto defer; }
-    if (!sock_listen(server, 16)) { err = "listen"; goto defer; }
+    if (!sock_listen(server)) { err = "listen"; goto defer; }
 
     Sock *client = sock_accept(server);
     if (client == NULL) { err = "accept"; goto defer; }

examples/02-hello_server_v6.c

@@ -12,7 +12,7 @@ int main(void)
 
     SockAddr addr = sock_addr("::", 6969);
     if (!sock_bind(server, addr)) { err = true; goto close; }
-    if (!sock_listen(server, 16)) { err = true; goto close; }
+    if (!sock_listen(server)) { err = true; goto close; }
 
     Sock *client = sock_accept(server);
     if (client == NULL) { err = true; goto close; }

examples/05-http_request.c

@@ -5,12 +5,16 @@
 
 int main(void)
 {
-    SockAddr addr = sock_addr("example.com", 80);
+    const char *domain_name = "example.com";
-    if (addr.type == SOCK_ADDR_INVALID) {
+    SockAddrList addr_list = sock_dns(domain_name, 80, SOCK_IPV4, SOCK_TCP);
-        fprintf(stderr, "ERROR: Could not resolve address %s\n", addr.str);
+    if (addr_list.count == 0) {
+        fprintf(stderr, "ERROR: Could not resolve address %s\n", domain_name);
         return 1;
     }
 
+    SockAddr addr = addr_list.items[0];
+    sock_addr_list_free(&addr_list);
+
     printf("%s:%d\n", addr.str, addr.port);
 
     Sock *s = sock_create(addr.type, SOCK_TCP);
@@ -30,7 +34,8 @@ int main(void)
     const char *req =
         "GET / HTTP/1.1\r\n"
         "Host: example.com\r\n"
-        "Connection: close\r\n\r\n";
+        "Connection: close\r\n"
+        "\r\n";
 
     sock_send(s, req, strlen(req));
 

examples/06-dig.c

@@ -0,0 +1,26 @@
+#define SOCK_IMPLEMENTATION
+#include "sock.h"
+
+int main(int argc, char **argv)
+{
+    const char *program_name = argv[0];
+
+    if (argc <= 1) {
+        fprintf(stderr, "USAGE: %s <address>\n", program_name);
+        fprintf(stderr, "ERROR: No address was provided\n");
+        return 1;
+    }
+
+    const char *arg_address = argv[1];
+
+    SockAddrList addrs = sock_dns(arg_address, 0, 0, SOCK_TCP);
+
+    for (size_t i = 0; i < addrs.count; ++i) {
+        SockAddr it = addrs.items[i];
+        printf("%s\n", it.str);
+    }
+
+    sock_addr_list_free(&addrs);
+
+    return 0;
+}

examples/10-chat_server.c

@@ -138,7 +138,7 @@ int main(void)
 
     printf("INFO: Bind socket\n");
 
-    if (!sock_listen(server, 10)) {
+    if (!sock_listen(server)) {
         fprintf(stderr, "ERROR: Could not listen on socket\n");
         sock_close(server);
         return EXIT_FAILURE;

sock.h

@@ -1,10 +1,160 @@
-// sock.h - v1.6.3 - MIT License - https://github.com/seajee/sock.h
+
+    /***************************************************************\
+    #                                                               #
+    #               @@@@@                                           #
+    #               @   @                                           #
+    #               @@@@@                                           #
+    #               @   @           sock.h - v1.7.0                 #
+    #               @   @             MIT License                   #
+    #            @@% .@ @                                           #
+    #         @@     @  @    https://github.com/seajee/sock.h       #
+    #        @ \    .@@                                             #
+    #         @ @@@#                                                #
+    #                                                               #
+    \***************************************************************/
+
+
+// sock.h - A single header library for network sockets management.
+//
+// [License and changelog]
+//
+//     See end of file.
+//
+// [Single header library usage]
+//
+//     Including this header file as such does what you normally expect.
+//
+//     If you also need to include all of the function implementations you
+//     need to #define SOCK_IMPLEMENTATION before including the header file
+//     like this:
+//
+//         #define SOCK_IMPLEMENTATION
+//         #include "sock.h"
+//
+// [Structure documentation]
+//
+//     Sock:         can be treated as a normal socket
+//
+//     SockAddr:     an address composed of an IP (v4 or v6) and a port
+//
+//         The fields you will commonly refer to in this structure are:
+//
+//         SockAddr addr;
+//         addr.port; // The port of the SockAddr
+//         addr.str;  // String representation of the address
+//
+//     SockAddrList: a dynamic array of SockAddr
+//
+//         A SockAddrList can be iterated like so:
+//
+//         SockAddrList list = ...;
+//         for (size_t i = 0; i < list.count; ++i) {
+//             SockAddr addr = list.items[i];
+//             // Try to connect to addr or just inspect it
+//         }
+//
+// [Function documentation]
+//
+// In this library all of the major functions are abstraction layers to common
+// standard functions, so their usage remain the same. Structures and utility
+// functions are put in place to simplify the usage of the standard C API for
+// socket and address handling.
+//
+// Sock related functions:
+//
+//     Sock *sock_create(SockAddrType domain, SockType type)
+//
+// Allocates and initializes a Sock with the corresponding domain and type.
+// When you're done using it you should close it with sock_close(). Returns
+// NULL on error.
+//
+//     bool sock_bind(Sock *sock, SockAddr addr)
+//
+// Binds a sock to the specified address. Returns false on error.
+//
+//     bool sock_listen(Sock *sock)
+//
+// Makes a sock listen for incoming connections. Returns false on error.
+//
+//     Sock *sock_accept(Sock *sock)
+//
+// Accepts a new connection on a sock in a blocking way. For handling new
+// connections asynchronously you can use sock_async_accept(). Returns NULL on
+// error.
+//
+//     bool sock_async_accept(Sock *sock, SockThreadCallback fn, void *user_data)
+//
+// Same as sock_accept but creates a new pthread that will own the client
+// sock. It will be the callback job to close the new sock. A function
+// callback shall be passed with the following signature:
+//     void callback(Sock *sock, void *user_data)
+// Returns false on error.
+//
+//     bool sock_connect(Sock *sock, SockAddr addr)
+//
+// Connects a sock on a connection-mode sock (e.g. TCP). Returns false on
+// error.
+//
+//     ssize_t sock_send(Sock *sock, const void *buf, size_t size)
+//
+// Same as send() but with socks: sends the content of buf to the specified
+// sock. On success returns the number of bytes sent. On error a negative
+// number shall be returned.
+//
+//     ssize_t sock_recv(Sock *sock, void *buf, size_t size)
+//
+// Same as recv() but with socks: receives a message from sock end writes it
+// into the specified buffer. On sucess returns the number of bytes received.
+// On error a negative number shall be returned.
+//
+//     ssize_t sock_sendto(Sock *sock, const void *buf, size_t size, SockAddr addr)
+//
+// Same as sendto() but with socks: the return value works the same way as
+// sock_send(). The addr parameter specifies the address to send the message
+// to.
+//
+//     ssize_t sock_recvfrom(Sock *sock, void *buf, size_t size, SockAddr *addr)
+//
+// Same as recvfrom() but with socks: the return value works the same way as
+// sock_recv(). The addr parameter will be filled with the address information
+// of the sender.
+//
+//     void sock_close(Sock *sock);
+//
+// Closes a sock and releases its memory.
+//
+//     void sock_log_error(const Sock *sock)
+//
+// Prints the last error message of the specified Sock in stderr. This
+// functions uses errno to get the error message.
+//
+// SockAddr related functions:
+//
+//     SockAddr sock_addr(const char *addr, int port)
+//
+// Given a valid IP (v4 or v6) address as a string and a port returns a
+// correctly initialized SockAddr structure. On invalid input, the resulting
+// SockAddr type will be set to SOCK_ADDR_INVALID.
+//
+//     SockAddrList sock_dns(const char *addr,
+//                  int port, SockAddrType addr_hint, SockType sock_hint)
+//
+// This functions queries information about the specified address (e.g.
+// "example.com") and returns a list of possible valid SockAddr. The only
+// required parameter is addr, while the rest are optional hints that can be
+// set to 0. Hints can be provided to further filter the resulting
+// SockAddrList. An empty list will be returned in case of no results or on
+// errors. Freeing the list is required after using it with
+// sock_addr_list_free().
+//
+//     void sock_addr_list_free(SockAddrList *list)
+//
+// Releases the memory of the specified SockAddrList.
 
 #ifndef SOCK_H_
 #define SOCK_H_
 
 #include <arpa/inet.h>
-#include <assert.h>
 #include <errno.h>
 #include <netdb.h>
 #include <pthread.h>
@@ -16,14 +166,16 @@
 #include <sys/types.h>
 #include <unistd.h>
 
+#define SOCK_ADDR_LIST_INITIAL_CAPACITY 16
+
 #ifdef __cplusplus
 extern "C" { // Prevent name mangling
 #endif // __cplusplus
 
 typedef enum {
     SOCK_ADDR_INVALID = 0,
-    SOCK_IPV4,
+    SOCK_IPV4 = AF_INET,
-    SOCK_IPV6
+    SOCK_IPV6 = AF_INET6
 } SockAddrType;
 
 typedef struct {
@@ -38,17 +190,23 @@ typedef struct {
     socklen_t len;
 } SockAddr;
 
+typedef struct {
+    SockAddr *items; // Dynamic array of SockAddr
+    size_t count;
+    size_t capacity;
+} SockAddrList;
+
 typedef enum {
     SOCK_TYPE_INVALID = 0,
-    SOCK_TCP,
+    SOCK_TCP = SOCK_STREAM,
-    SOCK_UDP
+    SOCK_UDP = SOCK_DGRAM
 } SockType;
 
 typedef struct {
     SockType type;    // Socket type
     SockAddr addr;    // Socket address
     int fd;           // File descriptor
-    char *last_error; // Last error about this socket
+    int last_errno;  // Last error about this socket
 } Sock;
 
 typedef void (*SockThreadCallback)(Sock *sock, void *user_data);
@@ -65,11 +223,17 @@ Sock *sock_create(SockAddrType domain, SockType type);
 // Create a SockAddr structure from primitives
 SockAddr sock_addr(const char *addr, int port);
 
+// Get all possible addresses from DNS with optional hints
+SockAddrList sock_dns(const char *addr, int port, SockAddrType addr_hint, SockType sock_hint);
+
+// Free a SockAddrList structure
+void sock_addr_list_free(SockAddrList *list);
+
 // Bind a socket to a specific address
 bool sock_bind(Sock *sock, SockAddr addr);
 
 // Make the socket listen to incoming connections
-bool sock_listen(Sock *sock, int backlog);
+bool sock_listen(Sock *sock);
 
 // Accept connections from a socket
 Sock *sock_accept(Sock *sock);
@@ -100,6 +264,7 @@ void sock_log_error(const Sock *sock);
 
 // Private functions
 void *sock__accept_thread(void *data);
+void sock__convert_addr(SockAddr *addr);
 
 #ifdef __cplusplus
 }
@@ -122,29 +287,7 @@ Sock *sock_create(SockAddrType domain, SockType type)
     memset(sock, 0, sizeof(*sock));
 
     sock->type = type;
-
+    sock->fd = socket(domain, type, 0);
-    int sock_domain = 0;
-    int sock_type = 0;
-
-    switch (domain) {
-        case SOCK_IPV4: sock_domain = AF_INET; break;
-        case SOCK_IPV6: sock_domain = AF_INET6; break;
-        default: {
-            free(sock);
-            return NULL;
-        } break;
-    }
-
-    switch (type) {
-        case SOCK_TCP: sock_type = SOCK_STREAM; break;
-        case SOCK_UDP: sock_type = SOCK_DGRAM; break;
-        default: {
-            free(sock);
-            return NULL;
-        } break;
-    }
-
-    sock->fd = socket(sock_domain, sock_type, 0);
     if (sock->fd < 0) {
         free(sock);
         return NULL;
@@ -153,6 +296,7 @@ Sock *sock_create(SockAddrType domain, SockType type)
     int enable = 1;
     if (setsockopt(sock->fd, SOL_SOCKET, SO_REUSEADDR,
                    &enable, sizeof(enable)) < 0) {
+        close(sock->fd);
         free(sock);
         return NULL;
     }
@@ -169,46 +313,116 @@ SockAddr sock_addr(const char *addr, int port)
         return sa;
     }
 
+    sa.port = port;
+
     if (inet_pton(AF_INET, addr, &sa.ipv4.sin_addr) == 1) {
         sa.type = SOCK_IPV4;
         sa.ipv4.sin_family = AF_INET;
         sa.ipv4.sin_port = htons(port);
         sa.len = sizeof(sa.ipv4);
-        strncpy(sa.str, addr, sizeof(sa.str));
+        snprintf(sa.str, sizeof(sa.str), "%s", addr);
     } else if (inet_pton(AF_INET6, addr, &sa.ipv6.sin6_addr) == 1) {
         sa.type = SOCK_IPV6;
         sa.ipv6.sin6_family = AF_INET6;
         sa.ipv6.sin6_port = htons(port);
         sa.len = sizeof(sa.ipv6);
-        strncpy(sa.str, addr, sizeof(sa.str));
+        snprintf(sa.str, sizeof(sa.str), "%s", addr);
-    } else {
+    }
-        struct addrinfo *res;
+
-        if (getaddrinfo(addr, NULL, NULL, &res) != 0) {
-            // TODO: specific errors from getaddrinfo are ignored for logging
-            sa.type = SOCK_ADDR_INVALID;
     return sa;
 }
 
-        if (res->ai_family == AF_INET) {
+SockAddrList sock_dns(const char *addr, int port, SockAddrType addr_hint, SockType sock_hint)
+{
+    SockAddrList list;
+    memset(&list, 0, sizeof(list));
+
+    if (addr == NULL) {
+        return list;
+    }
+
+    list.items = (SockAddr*)malloc(
+            sizeof(*list.items) * SOCK_ADDR_LIST_INITIAL_CAPACITY);
+    if (list.items == NULL) {
+        return list;
+    }
+    list.capacity = SOCK_ADDR_LIST_INITIAL_CAPACITY;
+
+    struct addrinfo hints;
+    memset(&hints, 0, sizeof(hints));
+    hints.ai_family = (addr_hint != SOCK_ADDR_INVALID ? addr_hint : AF_UNSPEC);
+    hints.ai_socktype = sock_hint;
+
+    char port_str[8];
+    snprintf(port_str, sizeof(port_str), "%d", port);
+
+    struct addrinfo *res;
+    if (getaddrinfo(addr, port_str, &hints, &res) != 0) {
+        return list;
+    }
+
+    for (struct addrinfo *ai = res; ai != NULL; ai = ai->ai_next) {
+        SockAddr sa;
+        memset(&sa, 0, sizeof(sa));
+
+        bool skip = false;
+
+        switch (ai->ai_family) {
+            case AF_INET: {
+                struct sockaddr_in *sin = (struct sockaddr_in*)ai->ai_addr;
                 sa.type = SOCK_IPV4;
-            sa.ipv4 = *(struct sockaddr_in*)res->ai_addr;
+                sa.port = ntohs(sin->sin_port);
-            sa.ipv4.sin_port = htons(port);
+                sa.ipv4 = *sin;
                 sa.len = sizeof(sa.ipv4);
                 inet_ntop(AF_INET, &sa.ipv4.sin_addr, sa.str, sizeof(sa.str));
-        } else {
+            } break;
+
+            case AF_INET6: {
+                struct sockaddr_in6 *sin6 = (struct sockaddr_in6*)ai->ai_addr;
                 sa.type = SOCK_IPV6;
-            sa.ipv6 = *(struct sockaddr_in6*)res->ai_addr;
+                sa.port = ntohs(sin6->sin6_port);
-            sa.ipv6.sin6_port = htons(port);
+                sa.ipv6 = *sin6;
                 sa.len = sizeof(sa.ipv6);
                 inet_ntop(AF_INET6, &sa.ipv6.sin6_addr, sa.str, sizeof(sa.str));
+            } break;
+
+            // Unreachable address family, skip address
+            default: {
+                skip = true;
+            } break;
+        }
+
+        if (skip) {
+            continue;
+        }
+
+        if (list.count >= list.capacity) {
+            list.capacity *= 2;
+            SockAddr *new_items = (SockAddr*)realloc(
+                    list.items, list.capacity * sizeof(*list.items));
+            if (new_items == NULL) {
+                sock_addr_list_free(&list);
+                return list;
+            }
+            list.items = new_items;
+        }
+        list.items[list.count++] = sa;
     }
 
     freeaddrinfo(res);
+
+    return list;
 }
 
-    sa.port = port;
+void sock_addr_list_free(SockAddrList *list)
+{
+    if (list == NULL) {
+        return;
+    }
 
-    return sa;
+    free(list->items);
+    list->count = 0;
+    list->capacity = 0;
 }
 
 bool sock_bind(Sock *sock, SockAddr addr)
@@ -218,7 +432,7 @@ bool sock_bind(Sock *sock, SockAddr addr)
     }
 
     if (bind(sock->fd, &addr.sockaddr, addr.len) < 0) {
-        sock->last_error = strerror(errno);
+        sock->last_errno = errno;
         return false;
     }
 
@@ -227,14 +441,14 @@ bool sock_bind(Sock *sock, SockAddr addr)
     return true;
 }
 
-bool sock_listen(Sock *sock, int backlog)
+bool sock_listen(Sock *sock)
 {
     if (sock == NULL) {
         return false;
     }
 
-    if (listen(sock->fd, backlog) < 0) {
+    if (listen(sock->fd, SOMAXCONN) < 0) {
-        sock->last_error = strerror(errno);
+        sock->last_errno = errno;
         return false;
     }
 
@@ -247,47 +461,25 @@ Sock *sock_accept(Sock *sock)
         return NULL;
     }
 
-    int fd = accept(sock->fd, &sock->addr.sockaddr, &sock->addr.len);
-    if (fd < 0) {
-        sock->last_error = strerror(errno);
-        return NULL;
-    }
-
     Sock *res = (Sock*)malloc(sizeof(*res));
     if (res == NULL) {
-        sock->last_error = strerror(errno);
+        sock->last_errno = errno;
         return NULL;
     }
     memset(res, 0, sizeof(*res));
 
+    res->addr.len = sock->addr.len;
+
+    int fd = accept(sock->fd, &res->addr.sockaddr, &res->addr.len);
+    if (fd < 0) {
+        free(res);
+        sock->last_errno = errno;
+        return NULL;
+    }
+
     res->type = sock->type;
     res->fd = fd;
-
+    sock__convert_addr(&res->addr);
-    SockAddr *addr = &res->addr;
-    addr->len = sizeof(addr->sockaddr);
-    getpeername(res->fd, &addr->sockaddr, &addr->len);
-    // TODO: This is duplicated code from sock_recvfrom
-    switch (addr->sockaddr.sa_family) {
-        case AF_INET: {
-            struct sockaddr_in *ipv4 = &addr->ipv4;
-            addr->type = SOCK_IPV4;
-            addr->port = ntohs(ipv4->sin_port);
-            addr->len = sizeof(*ipv4);
-            inet_ntop(AF_INET, &ipv4->sin_addr, addr->str, sizeof(addr->str));
-        } break;
-
-        case AF_INET6: {
-            struct sockaddr_in6 *ipv6 = &addr->ipv6;
-            addr->type = SOCK_IPV6;
-            addr->port = ntohs(ipv6->sin6_port);
-            addr->len = sizeof(*ipv6);
-            inet_ntop(AF_INET6, &ipv6->sin6_addr, addr->str, sizeof(addr->str));
-        } break;
-
-        default: {
-            assert(false && "Unreachable address family");
-        } break;
-    }
 
     return res;
 }
@@ -307,7 +499,7 @@ bool sock_async_accept(Sock *sock, SockThreadCallback fn, void *user_data)
         (SockThreadData*)malloc(sizeof(*thread_data));
     if (thread_data == NULL) {
         sock_close(client);
-        sock->last_error = strerror(errno);
+        sock->last_errno = errno;
         return false;
     }
 
@@ -319,7 +511,7 @@ bool sock_async_accept(Sock *sock, SockThreadCallback fn, void *user_data)
     if (pthread_create(&thread, NULL, sock__accept_thread, thread_data) != 0) {
         free(thread_data);
         sock_close(client);
-        sock->last_error = strerror(errno);
+        sock->last_errno = errno;
         return false;
     }
 
@@ -335,6 +527,7 @@ bool sock_connect(Sock *sock, SockAddr addr)
     }
 
     if (connect(sock->fd, &addr.sockaddr, addr.len) < 0) {
+        sock->last_errno = errno;
         return false;
     }
 
@@ -376,39 +569,27 @@ ssize_t sock_recvfrom(Sock *sock, void *buf, size_t size, SockAddr *addr)
         return -1;
     }
 
+    struct sockaddr_storage sa_storage;
     struct sockaddr *sa = NULL;
-    socklen_t *len = NULL;
+    socklen_t sa_len = 0;
+    socklen_t *len_ptr = NULL;
 
     if (addr != NULL) {
-        sa = &addr->sockaddr;
+        sa = (struct sockaddr*)&sa_storage;
-        len = &sock->addr.len;
+        sa_len = sizeof(sa_storage);
+        len_ptr = &sa_len;
     }
 
-    ssize_t res = recvfrom(sock->fd, buf, size, 0, sa, len);
+    ssize_t res = recvfrom(sock->fd, buf, size, 0, sa, len_ptr);
     if (res < 0 || addr == NULL) {
         return res;
     }
 
-    switch (addr->sockaddr.sa_family) {
+    if (addr != NULL) {
-        case AF_INET: {
+        memset(addr, 0, sizeof(*addr));
-            struct sockaddr_in *ipv4 = &addr->ipv4;
+        memcpy(&addr->sockaddr, sa, sa_len);
-            addr->type = SOCK_IPV4;
+        addr->len = sa_len;
-            addr->port = ntohs(ipv4->sin_port);
+        sock__convert_addr(addr);
-            addr->len = sizeof(*ipv4);
-            inet_ntop(AF_INET, &ipv4->sin_addr, addr->str, sizeof(addr->str));
-        } break;
-
-        case AF_INET6: {
-            struct sockaddr_in6 *ipv6 = &addr->ipv6;
-            addr->type = SOCK_IPV6;
-            addr->port = ntohs(ipv6->sin6_port);
-            addr->len = sizeof(*ipv6);
-            inet_ntop(AF_INET6, &ipv6->sin6_addr, addr->str, sizeof(addr->str));
-        } break;
-
-        default: {
-            assert(false && "Unreachable address family");
-        } break;
     }
 
     return res;
@@ -432,13 +613,7 @@ void sock_log_error(const Sock *sock)
         return;
     }
 
-    if (sock->last_error == NULL) {
+    fprintf(stderr, "SOCK ERROR: %s\n", strerror(sock->last_errno));
-        fprintf(stderr, "SOCK ERROR: socket is empty. errno says: %s\n",
-                strerror(errno));
-        return;
-    }
-
-    fprintf(stderr, "SOCK ERROR: %s\n", sock->last_error);
 }
 
 void *sock__accept_thread(void *data)
@@ -460,6 +635,35 @@ void *sock__accept_thread(void *data)
     return NULL;
 }
 
+void sock__convert_addr(SockAddr *addr)
+{
+    if (addr == NULL) {
+        return;
+    }
+
+    sa_family_t family = addr->sockaddr.sa_family;
+    switch (family) {
+        case AF_INET: {
+            struct sockaddr_in *ipv4 = &addr->ipv4;
+            addr->type = SOCK_IPV4;
+            addr->port = ntohs(ipv4->sin_port);
+            addr->len = sizeof(*ipv4);
+            inet_ntop(family, &ipv4->sin_addr, addr->str, sizeof(addr->str));
+        } break;
+
+        case AF_INET6: {
+            struct sockaddr_in6 *ipv6 = &addr->ipv6;
+            addr->type = SOCK_IPV6;
+            addr->port = ntohs(ipv6->sin6_port);
+            addr->len = sizeof(*ipv6);
+            inet_ntop(family, &ipv6->sin6_addr, addr->str, sizeof(addr->str));
+        } break;
+
+        default: {
+            addr->type = SOCK_ADDR_INVALID;
+        } break;
+    }
+}
 
 #ifdef __cplusplus
 }
@@ -470,6 +674,8 @@ void *sock__accept_thread(void *data)
 /*
     Revision history:
 
+        1.7.0 (2025-09-06) Header now includes documentation; New sock_dns()
+                           function; major improvements and refactoring
         1.6.3 (2025-08-24) Change SockThreadFn -> SockThreadCallback
         1.6.2 (2025-08-03) Log errno error if sock last error is NULL
         1.6.1 (2025-08-03) Log errno error if sock is NULL in sock_log_error