Fix error when decoding a NULL string

If some device info is NULL then this line would cause a RuntimeError: cannot use string() on <cdata 'char *' NULL>. For example, in my PC, the Intel CPU runtime under Linux has BUILT_IN_KERNELS = NULL.
inducer · Sep 7, 2016 · b1f9f04 · b1f9f04
1 parent 3128eb2
commit b1f9f04
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/pyopencl/cffi_cl.py b/pyopencl/cffi_cl.py
@@ -99,7 +99,7 @@ def _py_call(handle, status):
     _bytes = bytes
 
     def _ffi_pystr(s):
-        return _ffi.string(s).decode()
+        return _ffi.string(s).decode() if s else None
 else:
     try:
         _bytes = bytes