Allow embed option to take function name.

Cython/Compiler/CmdLine.py

@@ -34,7 +34,7 @@ Options:
   -a, --annotate                 Produce a colorized HTML version of the source.
   --line-directives              Produce #line directives pointing to the .pyx source
   --cplus                        Output a C++ rather than C file.
-  --embed                        Generate a main() function that embeds the Python interpreter.
+  --embed[=<method_name>]        Generate a main() function that embeds the Python interpreter.
   -2                             Compile based on Python-2 syntax and code semantics.
   -3                             Compile based on Python-3 syntax and code semantics.
   --fast-fail                    Abort the compilation on the first error
@@ -84,8 +84,12 @@ def parse_command_line(args):
                 options.use_listing_file = 1
             elif option in ("-+", "--cplus"):
                 options.cplus = 1
-            elif option == "--embed":
-                Options.embed = True
+            elif option.startswith("--embed"):
+                ix = option.find('=')
+                if ix == -1:
+                    Options.embed = "main"
+                else:
+                    Options.embed = option[ix+1:]
             elif option.startswith("-I"):
                 options.include_path.append(get_param(option))
             elif option == "--include-dir":

Cython/Compiler/ModuleNode.py

@@ -1897,7 +1897,16 @@ class ModuleNode(Nodes.Node, Nodes.BlockNode):
 
     def generate_main_method(self, env, code):
         module_is_main = "%s%s" % (Naming.module_is_main, self.full_module_name.replace('.', '__'))
-        code.globalstate.use_utility_code(main_method.specialize(module_name=env.module_name, module_is_main=module_is_main))
+        if Options.embed == "main":
+            wmain = "wmain"
+        else:
+            wmain = Options.embed
+        code.globalstate.use_utility_code(
+            main_method.specialize(
+                module_name = env.module_name,
+                module_is_main = module_is_main,
+                main_method = Options.embed,
+                wmain_method = wmain))
 
     def generate_pymoduledef_struct(self, env, code):
         if env.doc:
@@ -2646,9 +2655,9 @@ impl = """
 #endif
 
 #if PY_MAJOR_VERSION < 3
-int main(int argc, char** argv) {
+int %(main_method)s(int argc, char** argv) {
 #elif defined(WIN32) || defined(MS_WINDOWS)
-int wmain(int argc, wchar_t **argv) {
+int %(wmain_method)s(int argc, wchar_t **argv) {
 #else
 static int __Pyx_main(int argc, wchar_t **argv) {
 #endif
@@ -2665,9 +2674,13 @@ static int __Pyx_main(int argc, wchar_t **argv) {
     m = fpgetmask();
     fpsetmask(m & ~FP_X_OFL);
 #endif
+    if (argc) {
         Py_SetProgramName(argv[0]);
+    }
     Py_Initialize();
+    if (argc) {
         PySys_SetArgv(argc, argv);
+    }
     %(module_is_main)s = 1;
 #if PY_MAJOR_VERSION < 3
         init%(module_name)s();
@@ -2794,8 +2807,12 @@ oom:
 }
 
 int
-main(int argc, char **argv)
+%(main_method)s(int argc, char **argv)
 {
+    if (!argc) {
+        return __Pyx_main(0, NULL);
+    }
+    else {
         wchar_t **argv_copy = (wchar_t **)malloc(sizeof(wchar_t*)*argc);
         /* We need a second copies, as Python might modify the first one. */
         wchar_t **argv_copy2 = (wchar_t **)malloc(sizeof(wchar_t*)*argc);
@@ -2821,6 +2838,7 @@ main(int argc, char **argv)
         free(argv_copy);
         free(argv_copy2);
         return res;
+    }
 }
 #endif
 """)

Cython/Compiler/Options.py

@@ -44,9 +44,9 @@ lookup_module_cpdef = 0
 init_local_none = 1
 
 # Whether or not to embed the Python interpreter, for use in making a
-# standalone executable. This will provide a main() method which simply
-# executes the body of this module.
-embed = False
+# standalone executable or calling from external libraries.
+# This will provide a method which simply executes the body of this module.
+embed = None
 
 # Disables function redefinition, allowing all functions to be declared at
 # module creation time. For legacy code only.