Add \mainpage to the C API documentation

The main page contains a reference to the header containing all
functions of the C API and a short example of how to use it.

1 files changed, 46 insertions, 0 deletions

diff --git a/NK_C_API.h b/NK_C_API.h
index 289eaee..c803ef1 100644
--- a/NK_C_API.h
+++ b/NK_C_API.h
@@ -37,6 +37,52 @@
  * \file
  *
  * C API for libnitrokey
+ *
+ * \mainpage
+ *
+ * **libnitrokey** provides access to Nitrokey Pro and Nitrokey Storage devices.
+ * This documentation describes libnitrokey’s C API.  For a list of the
+ * available functions, see the NK_C_API.h file.
+ *
+ * \section getting_started Example
+ *
+ * \code{.c}
+ * #include <stdio.h>
+ * #include <stdlib.h>
+ * #include <libnitrokey/NK_C_API.h>
+ *
+ * int main(void)
+ * {
+ *         if (NK_login_auto() != 1) {
+ *                 fprintf(stderr, "No Nitrokey found.\n");
+ *                 return 1;
+ *         }
+ *
+ *         NK_device_model model = NK_get_device_model();
+ *         printf("Connected to ");
+ *         switch (model) {
+ *         case NK_PRO:
+ *                 printf("a Nitrokey Pro");
+ *                 break;
+ *         case NK_STORAGE:
+ *                 printf("a Nitrokey Storage");
+ *                 break;
+ *         default:
+ *                 printf("an unsupported Nitrokey");
+ *                 break;
+ *         }
+ *
+ *         char* serial_number = NK_device_serial_number();
+ *         if (serial_number)
+ *             printf(" with serial number %s\n", serial_number);
+ *         else
+ *             printf(" -- could not query serial number!\n");
+ *         free(serial_number);
+ *
+ *         NK_logout();
+ *         return 0;
+ * }
+ * \endcode
  */
 
 #ifdef __cplusplus