network: comment libgcrypt initalization process

[collectd.git] / src / network.c

diff --git a/src/network.c b/src/network.c
index be82c6f..f379a5c 100644 (file)
--- a/src/network.c
+++ b/src/network.c
@@ -500,8 +500,15 @@ static void network_init_gcrypt (void) /* {{{ */
   if (gcry_control (GCRYCTL_ANY_INITIALIZATION_P))
     return;
 
+ /* http://www.gnupg.org/documentation/manuals/gcrypt/Multi_002dThreading.html
+  * To ensure thread-safety, it's important to set GCRYCTL_SET_THREAD_CBS
+  * *before* initalizing Libgcrypt with gcry_check_version(), which itself must
+  * be called before any other gcry_* function. GCRYCTL_ANY_INITIALIZATION_P
+  * above doesn't count, as it doesn't implicitly initalize Libgcrypt.
+  *
+  * tl;dr: keep all these gry_* statements in this exact order please. */
   gcry_control (GCRYCTL_SET_THREAD_CBS, &gcry_threads_pthread);
-  gcry_check_version (NULL); /* before calling *almost* any other functions */
+  gcry_check_version (NULL);
   gcry_control (GCRYCTL_INIT_SECMEM, 32768);
   gcry_control (GCRYCTL_INITIALIZATION_FINISHED);
 } /* }}} void network_init_gcrypt */