diff --git a/RELICENSE/casaroli.md b/RELICENSE/casaroli.md
new file mode 100644
index 00000000..97ea9285
--- /dev/null
+++ b/RELICENSE/casaroli.md
@@ -0,0 +1,16 @@
+# Permission to Relicense under MPLv2 or any other OSI approved license chosen by the current ZeroMQ BDFL
+
+This is a statement by Marco Casaroli that grants permission to
+relicense its copyrights in the libzmq C++ library (ZeroMQ) under the
+Mozilla Public License v2 (MPLv2) or any other Open Source Initiative
+approved license chosen by the current ZeroMQ BDFL (Benevolent
+Dictator for Life).
+
+A portion of the commits made by the Github handle "casaroli", with
+commit author "Marco Casaroli <marco.casaroli@gmail.com>", are
+copyright of Marco Casaroli.  This document hereby grants the libzmq
+project team to relicense libzmq, including all past, present and
+future contributions of the author listed above.
+
+Marco Casaroli
+2023/2/2
diff --git a/src/blob.hpp b/src/blob.hpp
index 06a41913..d84bba64 100644
--- a/src/blob.hpp
+++ b/src/blob.hpp
@@ -81,7 +81,7 @@ struct blob_t
         _size (size_),
         _owned (true)
     {
-        alloc_assert (_data);
+        alloc_assert (!_size || _data);
     }
 
     //  Creates a blob_t of a given size, an initializes content by copying
@@ -91,8 +91,10 @@ struct blob_t
         _size (size_),
         _owned (true)
     {
-        alloc_assert (_data);
-        memcpy (_data, data_, size_);
+        alloc_assert (!size_ || _data);
+        if (size_ && _data) {
+            memcpy (_data, data_, size_);
+        }
     }
 
     //  Creates a blob_t for temporary use that only references a
@@ -126,10 +128,12 @@ struct blob_t
     {
         clear ();
         _data = static_cast<unsigned char *> (malloc (other_._size));
-        alloc_assert (_data);
+        alloc_assert (!other_._size || _data);
         _size = other_._size;
         _owned = true;
-        memcpy (_data, other_._data, _size);
+        if (_size && _data) {
+            memcpy (_data, other_._data, _size);
+        }
     }
 
     //  Sets a blob_t to a copy of a given buffer.
@@ -137,10 +141,12 @@ struct blob_t
     {
         clear ();
         _data = static_cast<unsigned char *> (malloc (size_));
-        alloc_assert (_data);
+        alloc_assert (!size_ || _data);
         _size = size_;
         _owned = true;
-        memcpy (_data, data_, size_);
+        if (size_ && _data) {
+            memcpy (_data, data_, size_);
+        }
     }
 
     //  Empties a blob_t.
diff --git a/src/err.hpp b/src/err.hpp
index 3f3278f8..c283e6a5 100644
--- a/src/err.hpp
+++ b/src/err.hpp
@@ -172,7 +172,7 @@ int wsa_error_to_errno (int errcode_);
 //  Provides convenient way to check whether memory allocation have succeeded.
 #define alloc_assert(x)                                                        \
     do {                                                                       \
-        if (unlikely (!x)) {                                                   \
+        if (unlikely (!(x))) {                                                 \
             fprintf (stderr, "FATAL ERROR: OUT OF MEMORY (%s:%d)\n", __FILE__, \
                      __LINE__);                                                \
             fflush (stderr);                                                   \