What causes "ares_library_init: %s " in nodejs/node?

Check the ares_strerror() output in the message to identify the specific failure code (e.g., ARES_EFORMERR for internal format errors).

nodejs/node · critical

ares_library_init: %s

Error message

ares_library_init: %s

What it means

Printed by adig's main() at adig.c:1497 when ares_library_init(ARES_LIB_INIT_ALL) returns a status other than ARES_SUCCESS. This call initializes the c-ares library's global state (including WinSock startup on Windows). The error string from ares_strerror() is included. The tool returns 1 immediately — no channel is created, no queries are issued.

Source

Thrown at deps/cares/src/tools/adig.c:1497

    global_config.options.ndomains  = 1;
  }
}

int main(int argc, char **argv)
{
  ares_channel_t *channel = NULL;
  ares_status_t   status;
  int             rv = 0;

#ifdef USE_WINSOCK
  WORD    wVersionRequested = MAKEWORD(USE_WINSOCK, USE_WINSOCK);
  WSADATA wsaData;
  WSAStartup(wVersionRequested, &wsaData);
#endif

  status = (ares_status_t)ares_library_init(ARES_LIB_INIT_ALL);
  if (status != ARES_SUCCESS) {
    fprintf(stderr, "ares_library_init: %s\n", ares_strerror((int)status));
    return 1;
  }

  config_defaults();

  if (!read_cmdline(argc, (const char * const *)argv, 1)) {
    printf("\n** ERROR: %s\n\n", global_config.error);
    print_help();
    rv = 1;
    goto done;
  }

  if (global_config.no_rcfile && !read_rcfile()) {
    fprintf(stderr, "\n** ERROR: %s\n", global_config.error);
  }

  if (global_config.is_help) {
    print_help();

View on GitHub (pinned to 1b2de5e052)

Solutions

Check the ares_strerror() output in the message to identify the specific failure code (e.g., ARES_EFORMERR for internal format errors).
On Windows, verify that WSAStartup succeeded — check the USE_WINSOCK version constant matches the installed WinSock.
Ensure ares_library_init is called exactly once per process (or use reference counting) and matched with ares_library_cleanup.
Rebuild adig and c-ares from the same source version to avoid ABI mismatches.

Example fix

// before: double-init or version mismatch
ares_library_init(ARES_LIB_INIT_ALL);  // first call (e.g., in another lib)
// adig's main() calls ares_library_init again
// -> 'ares_library_init: ...'

// after: init once, cleanup once
status = ares_library_init(ARES_LIB_INIT_ALL);
if (status != ARES_SUCCESS) { /* handle */ }
// ... use c-ares ...
ares_library_cleanup();  // exactly once at shutdown

Defensive patterns

Strategy: validation

Validate before calling

// Call ares_library_init exactly once per process
static int lib_initialized = 0;
if (!lib_initialized) {
    ares_status_t status = (ares_status_t)ares_library_init(ARES_LIB_INIT_ALL);
    if (status != ARES_SUCCESS) {
        fprintf(stderr, "init failed: %s\n", ares_strerror((int)status));
        return -1;
    }
    lib_initialized = 1;
}
// at process exit: ares_library_cleanup();

Try / catch

ares_status_t status = (ares_status_t)ares_library_init(ARES_LIB_INIT_ALL);
if (status != ARES_SUCCESS) {
    fprintf(stderr, "ares_library_init: %s\n", ares_strerror((int)status));
    // do not proceed to channel creation; exit or fall back
    return EXIT_FAILURE;
}

Prevention

Initialize c-ares exactly once per process and clean up exactly once at exit.
Match c-ares header version with the linked shared library.
On Windows, verify WSAStartup succeeds before calling ares_library_init.

When it happens

Trigger: Calling ares_library_init(ARES_LIB_INIT_ALL) at the start of adig's main() (line 1496). Fails when the library cannot initialize its internal subsystems — on Windows if WSAStartup failed earlier (line 1488), or if the library was compiled without required features. Also fails if ares_library_init has already been called without a matching ares_library_cleanup (double-init).

Common situations: On Windows, WSAStartup fails due to a WinSock version mismatch or resource limitation. The c-ares shared library version is incompatible with the headers the tool was compiled against. The library was built with ARES_LIB_INIT_ALL but the platform lacks a required init component. Another part of the application already called ares_library_init.

Related errors

AI-assisted analysis of nodejs/node@1b2de5e052 (2026-08-13). Data as JSON: /api/errors/e60bfe416547036e. Report an issue: GitHub.