doc: clarify thread safeness in gnutls_global_init()

This documents and clarifies the thread safeness of gnutls_global_init()
and its constraints.

Resolves: #900

Signed-off-by: Nikos Mavrogiannopoulos <nmav@redhat.com>

2 files changed, 4 insertions, 2 deletions

diff --git a/doc/cha-gtls-app.texi b/doc/cha-gtls-app.texi
index 74fed786b7..969aa5c86f 100644
--- a/doc/cha-gtls-app.texi
+++ b/doc/cha-gtls-app.texi
@@ -364,7 +364,9 @@ The GnuTLS library is initialized on load; prior to 3.3.0 was initialized by cal
 The original behavior of requiring explicit initialization can obtained by setting the
 GNUTLS_NO_EXPLICIT_INIT environment variable to 1, or by using the macro GNUTLS_SKIP_GLOBAL_INIT
 in a global section of your program --the latter works in systems with
-support for weak symbols only.}. 
+support for weak symbols only.}. @funcref{gnutls_global_init} in
+versions after 3.3.0 is thread-safe (see @ref{Thread safety}).
+
 The initialization typically enables CPU-specific acceleration, performs any required
 precalculations needed, opens any required system devices (e.g., /dev/urandom on Linux)
 and initializes subsystems that could be used later.
diff --git a/lib/global.c b/lib/global.c
index 334148342e..b42fcb2632 100644
--- a/lib/global.c
+++ b/lib/global.c
@@ -211,7 +211,7 @@ static int _gnutls_init_ret = 0;
  * called as many times as gnutls_global_init().  This is useful when
  * GnuTLS is used by more than one library in an application.  This
  * function can be called many times, but will only do something the
- * first time.
+ * first time. It is thread safe since GnuTLS 3.3.0.
  *
  * A subsequent call of this function if the initial has failed will
  * return the same error code.