the log wrapper in C/C++ accepts formats

pam-module/examples/logging_example.c

@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: Apache-2.0
+// C example demonstrating printf-style Rust logging wrapper
+
+#include "../include/rust_backend_ffi.h"
+
+int main(int argc, char** argv) {
+    (void)argc; (void)argv;
+    // Ensure logger is initialized (nullptr -> default path)
+    rust_init_logging(NULL);
+
+    const char* user = "alice";
+    int result = 0; // pretend success
+
+    RUST_LOGF_INFO("C example: user=%s authenticated=%d", user, result);
+    RUST_LOGF_DEBUG("C example: debug details: x=%d y=%d", 10, 20);
+
+    return 0;
+}