diff --git a/lexor.lex b/lexor.lex
index d9e02dd96..e30d7deaa 100644
--- a/lexor.lex
+++ b/lexor.lex
@@ -899,7 +899,7 @@ TU [munpf]
   }
 
 `[a-zA-Z_]+ {
-      yywarn(yylloc, "macro replacement not supported. "
+      yywarn(yylloc, "warning: macro replacement not supported. "
              "Use an external preprocessor.");
   }
 
@@ -941,7 +941,8 @@ static unsigned truncate_to_integer_width(verinum::V*bits, unsigned size)
 
       for (unsigned idx = integer_width; idx < size; idx += 1) {
 	    if (bits[idx] != pad) {
-		  yywarn(yylloc, "Unsized numeric constant truncated to integer width.");
+		  yywarn(yylloc, "warning: Unsized numeric constant truncated "
+                                 "to integer width.");
 		  break;
 	    }
       }
@@ -985,7 +986,7 @@ verinum*make_unsized_binary(const char*txt)
       }
 
       if ((based_size > 0) && (size > based_size)) yywarn(yylloc,
-          "extra digits given for sized binary constant.");
+          "warning: extra digits given for sized binary constant.");
 
       verinum::V*bits = new verinum::V[size];
 
@@ -1050,7 +1051,7 @@ verinum*make_unsized_octal(const char*txt)
             int rem = based_size % 3;
 	    if (rem != 0) based_size += 3 - rem;
 	    if (size > based_size) yywarn(yylloc,
-	        "extra digits given for sized octal constant.");
+	        "warning: extra digits given for sized octal constant.");
       }
 
       verinum::V*bits = new verinum::V[size];
@@ -1119,7 +1120,7 @@ verinum*make_unsized_hex(const char*txt)
             int rem = based_size % 4;
 	    if (rem != 0) based_size += 4 - rem;
 	    if (size > based_size) yywarn(yylloc,
-	        "extra digits given for sized hex constant.");
+	        "warning: extra digits given for sized hex constant.");
       }
 
       verinum::V*bits = new verinum::V[size];
diff --git a/parse.y b/parse.y
index 8da3e535b..3a1d1cb88 100644
--- a/parse.y
+++ b/parse.y
@@ -6068,7 +6068,7 @@ specify_path_identifiers
       }
   | IDENTIFIER '[' expr_primary ']'
       { if (gn_specify_blocks_flag) {
-	      yywarn(@4, "Bit selects are not currently supported "
+	      yywarn(@4, "warning: Bit selects are not currently supported "
 			 "in path declarations. The declaration "
 			 "will be applied to the whole vector.");
 	}
@@ -6079,7 +6079,7 @@ specify_path_identifiers
       }
   | IDENTIFIER '[' expr_primary polarity_operator expr_primary ']'
       { if (gn_specify_blocks_flag) {
-	      yywarn(@4, "Part selects are not currently supported "
+	      yywarn(@4, "warning: Part selects are not currently supported "
 			 "in path declarations. The declaration "
 			 "will be applied to the whole vector.");
 	}
@@ -6096,7 +6096,7 @@ specify_path_identifiers
       }
   | specify_path_identifiers ',' IDENTIFIER '[' expr_primary ']'
       { if (gn_specify_blocks_flag) {
-	      yywarn(@4, "Bit selects are not currently supported "
+	      yywarn(@4, "warning: Bit selects are not currently supported "
 			 "in path declarations. The declaration "
 			 "will be applied to the whole vector.");
 	}
@@ -6107,7 +6107,7 @@ specify_path_identifiers
       }
   | specify_path_identifiers ',' IDENTIFIER '[' expr_primary polarity_operator expr_primary ']'
       { if (gn_specify_blocks_flag) {
-	      yywarn(@4, "Part selects are not currently supported "
+	      yywarn(@4, "warning: Part selects are not currently supported "
 			 "in path declarations. The declaration "
 			 "will be applied to the whole vector.");
 	}
diff --git a/parse_misc.cc b/parse_misc.cc
index 95c64dbb4..1ffb833f8 100644
--- a/parse_misc.cc
+++ b/parse_misc.cc
@@ -70,7 +70,7 @@ void VLerror(const YYLTYPE&loc, const char*msg, ...)
 void VLwarn(const YYLTYPE&loc, const char*msg)
 {
       warn_count += 1;
-      cerr << loc << ": warning: " << msg << endl;
+      cerr << loc << ": " << msg << endl;
 }
 
 int VLwrap()
diff --git a/pform.cc b/pform.cc
index fc61b9657..1a13ca249 100644
--- a/pform.cc
+++ b/pform.cc
@@ -2048,7 +2048,7 @@ void pform_make_udp(const struct vlltype&loc, perm_string name,
 
 	// Put the primitive into the primitives table
       if (pform_primitives[name]) {
-	    VLwarn("UDP primitive already exists.");
+	    VLwarn("warning: UDP primitive already exists.");
 
       } else {
 	    PUdp*udp = new PUdp(name, parms->size());