diff --git a/pyopencl/c_wrapper/wrap_cl_core.h b/pyopencl/c_wrapper/wrap_cl_core.h
index 1393b0e8cff954e90efced39b72f2e37b732c604..bc25d4a99e977204565cfe6a539a0adef6571d05 100644
--- a/pyopencl/c_wrapper/wrap_cl_core.h
+++ b/pyopencl/c_wrapper/wrap_cl_core.h
@@ -44,7 +44,7 @@ error *_create_command_queue(void **ptr_command_queue, void *ptr_context, void *
 error *_create_buffer(void **ptr_buffer, void *ptr_context, cl_mem_flags flags, size_t size, void *hostbuf);
 error *_create_program_with_source(void **ptr_program, void *ptr_context, const char *src);
 error *_create_program_with_binary(void **ptr_program, void *ptr_context, cl_uint num_devices, void **ptr_devices, cl_uint num_binaries, char **binaries, size_t *binary_sizes);
-error *program__build(void *ptr_program, char *options, cl_uint num_devices, void **ptr_devices);
+error *program__build(void *ptr_program, const char *options, cl_uint num_devices, void **ptr_devices);
 error *program__kind(void *ptr_program, int *kind);
 error *program__get_build_info(void *ptr_program, void *ptr_device, cl_program_build_info param, generic_info *out);
 
@@ -53,7 +53,7 @@ error *_create_sampler(void **ptr_sampler, void *ptr_context, int normalized_coo
 error *event__get_profiling_info(void *ptr_event, cl_profiling_info param, generic_info *out);
 error *event__wait(void *ptr_event);
 
-error *_create_kernel(void **ptr_kernel, void *ptr_program, char *name);
+error *_create_kernel(void **ptr_kernel, void *ptr_program, const char *name);
 error *kernel__set_arg_null(void *ptr_kernel, cl_uint arg_index);
 error *kernel__set_arg_mem(void *ptr_kernel, cl_uint arg_index, void *ptr_mem);
 error *kernel__set_arg_sampler(void *ptr_kernel, cl_uint arg_index, void *ptr_sampler);
diff --git a/pyopencl/cffi_cl.py b/pyopencl/cffi_cl.py
index c82a4ae65e5591ddf516ce3a21bed3c816fdddde..0f311f640e0ffdb3b7149804375eea0c911ac6a5 100644
--- a/pyopencl/cffi_cl.py
+++ b/pyopencl/cffi_cl.py
@@ -38,6 +38,21 @@ from pyopencl._cffi import _ffi, _lib
 # are we running on pypy?
 _PYPY = '__pypy__' in sys.builtin_module_names
 
+try:
+    _unicode = unicode
+except:
+    _unicode = str
+    _bytes = bytes
+else:
+    try:
+        _bytes = bytes
+    except:
+        _bytes = str
+
+def _convert_str(s):
+    if isinstance(s, _unicode):
+        return s.encode()
+    return s
 
 # {{{ wrapper tools
 
@@ -553,7 +568,7 @@ class _Program(_Common):
     def _init_source(self, context, src):
         ptr_program = _ffi.new('void **')
         _handle_error(_lib._create_program_with_source(
-            ptr_program, context.ptr, _ffi.new('char[]', src)))
+            ptr_program, context.ptr, _convert_str(src)))
         self.ptr = ptr_program[0]
 
     def _init_binary(self, context, devices, binaries):
@@ -597,7 +612,7 @@ class _Program(_Common):
 
         _handle_error(
                 _lib.program__build(self.ptr,
-                    _ffi.new('char[]', options), num_devices,
+                    _convert_str(options), num_devices,
                     _ffi.cast('void**', ptr_devices)))
 
     def get_build_info(self, device, param):
@@ -616,7 +631,8 @@ class Kernel(_Common):
 
     def __init__(self, program, name):
         ptr_kernel = _ffi.new('void **')
-        _handle_error(_lib._create_kernel(ptr_kernel, program.ptr, name))
+        _handle_error(_lib._create_kernel(ptr_kernel, program.ptr,
+                                          _convert_str(name)))
         self.ptr = ptr_kernel[0]
 
     def set_arg(self, arg_index, arg):
diff --git a/src/c_wrapper/wrap_cl.cpp b/src/c_wrapper/wrap_cl.cpp
index ba0cf69e0cf766a8766102246361a59ff139b081..717e94f0121069d4a81a2da53631be848e621a1b 100644
--- a/src/c_wrapper/wrap_cl.cpp
+++ b/src/c_wrapper/wrap_cl.cpp
@@ -2362,7 +2362,7 @@ namespace pyopencl
         }
       }
 
-      void build(char *options, cl_uint num_devices, void **ptr_devices)
+      void build(const char *options, cl_uint num_devices, void **ptr_devices)
       {
         // todo: this function should get a list of device instances, not raw pointers
         // pointers are for the cffi interface and should not be here
@@ -2520,13 +2520,12 @@ namespace pyopencl
         PYOPENCL_CALL_GUARDED(clRetainKernel, (knl));
     }
 
-    kernel(program const &prg, std::string const &kernel_name)
+    kernel(program const &prg, const char *kernel_name)
     {
       cl_int status_code;
 
       PYOPENCL_PRINT_CALL_TRACE("clCreateKernel");
-      m_kernel = clCreateKernel(prg.data(), kernel_name.c_str(),
-                                &status_code);
+      m_kernel = clCreateKernel(prg.data(), kernel_name, &status_code);
       if (status_code != CL_SUCCESS)
         throw pyopencl::error("clCreateKernel", status_code);
     }
@@ -3027,8 +3026,8 @@ void pyopencl_free_pointer_array(void **p, uint32_t size)
   return 0;
 }
 
-::error *program__build(
-    void *ptr_program, char *options, cl_uint num_devices, void **ptr_devices)
+::error *program__build(void *ptr_program, const char *options,
+                        cl_uint num_devices, void **ptr_devices)
 {
 
   BEGIN_C_HANDLE_ERROR
@@ -3116,7 +3115,8 @@ void pyopencl_free_pointer_array(void **p, uint32_t size)
 
 // {{{ kernel
 
-::error *_create_kernel(void **ptr_kernel, void *ptr_program, char *name) {
+::error *_create_kernel(void **ptr_kernel, void *ptr_program,
+                        const char *name) {
   pyopencl::program *prg = static_cast<pyopencl::program*>(ptr_program);
 
   BEGIN_C_HANDLE_ERROR