1 files changed, 8 insertions, 3 deletions
diff --git a/pp2cc.py b/pp2cc.py
index 27c0fa1..99585c4 100755
--- a/pp2cc.py
+++ b/pp2cc.py
@@ -1397,6 +1397,8 @@ Options:
     -D name
     -D name=definition This option is passed to the cpp program, and acts like
                     adding #define name or #define name definition respectively
+    -U name         This option is passed to the cpp program and acts like
+                    adding #undef name
     --no-cpp        Disable the use of the C Preprocessor
     """
     try:
@@ -1421,9 +1423,12 @@ Options:
                         set_arg = "output_filename"
                     elif arg == "--tree":
                         settings["dump_parsed_files"] = True
-                    elif arg == "-D":
-                        settings["cpp_args"].append("-D")
-                        set_arg = "cpp_args"
+                    elif arg[1] in ("D", "U"):
+                        settings["cpp_args"].append(arg)
+                        if len(arg) == 2:
+                            # Support -Dmacro=defn and -D macro=defn and
+                            # -Umacro and -U macro
+                            set_arg = "cpp_args"
                     elif arg == "--no-cpp":
                         settings["use_cpp"] = False
                     elif arg == "-h" or arg == "--help" or arg == "--usage":