diff --git a/src/main.c b/src/main.c
index 45f1868..24f71c9 100644
--- a/src/main.c
+++ b/src/main.c
@@ -24,6 +24,10 @@
 #include <errno.h>
 #include "CPP.h"
 
+#ifndef PROGNAME_CPP
+# define PROGNAME_CPP	"cpp"
+#endif
+
 
 /* cpp */
 /* private */
@@ -62,13 +66,13 @@ static int _cpp(Prefs * prefs, int filec, char * filev[])
 	if(prefs->outfile == NULL)
 		fp = stdout;
 	else if((fp = fopen(prefs->outfile, "w")) == NULL)
-		return error_set_print("cpp", 1, "%s: %s", prefs->outfile,
-				strerror(errno));
+		return error_set_print(PROGNAME_CPP, 1, "%s: %s",
+				prefs->outfile, strerror(errno));
 	for(i = 0; i < filec; i++)
 		ret |= _cpp_do(prefs, fp, filev[i]);
 	if(fclose(fp) != 0)
-		return error_set_print("cpp", 1, "%s: %s", prefs->outfile,
-				strerror(errno));
+		return error_set_print(PROGNAME_CPP, 1, "%s: %s",
+				prefs->outfile, strerror(errno));
 	return ret;
 }
 
@@ -143,7 +147,7 @@ static void _do_print_token(FILE * fp, Token * token)
 /* cpp_error */
 static int _cpp_error(void)
 {
-	return error_print("cpp");
+	return error_print(PROGNAME_CPP);
 }
 
 
@@ -151,7 +155,7 @@ static int _cpp_error(void)
 /* FIXME -E prints metadata? */
 static int _usage(void)
 {
-	fputs("Usage: cpp [-D name[=value]]...[-I directory][-o file][-t][-U name]... input...\n"
+	fputs("Usage: " PROGNAME_CPP " [-D name[=value]]...[-I directory][-o file][-t][-U name]... input...\n"
 "  -D	Add a substitution\n"
 "  -I	Add a directory to the search path\n"
 "  -o	Write output to a file\n"
@@ -218,7 +222,7 @@ static int _main_add_define(Prefs * prefs, char * define)
 	value = strtok(define, "=");
 	if((p = realloc(prefs->defines, sizeof(*p) * (prefs->defines_cnt + 1)))
 			== NULL)
-		return error_set_print("cpp", 1, "%s", strerror(errno));
+		return error_set_print(PROGNAME_CPP, 1, "%s", strerror(errno));
 	prefs->defines = p;
 	prefs->defines[prefs->defines_cnt++] = define;
 	return 0;
@@ -230,7 +234,7 @@ static int _main_add_path(Prefs * prefs, char const * path)
 
 	if((p = realloc(prefs->paths, sizeof(*p) * (prefs->paths_cnt + 1)))
 			== NULL)
-		return error_set_print("cpp", 1, "%s", strerror(errno));
+		return error_set_print(PROGNAME_CPP, 1, "%s", strerror(errno));
 	prefs->paths = p;
 	prefs->paths[prefs->paths_cnt++] = path;
 	return 0;
@@ -244,7 +248,7 @@ static int _main_add_undefine(Prefs * prefs, char const * undefine)
 		return 1;
 	if((p = realloc(prefs->undefines, sizeof(*p)
 					* (prefs->undefines_cnt + 1))) == NULL)
-		return error_set_print("cpp", 1, "%s", strerror(errno));
+		return error_set_print(PROGNAME_CPP, 1, "%s", strerror(errno));
 	prefs->undefines = p;
 	prefs->undefines[prefs->undefines_cnt++] = undefine;
 	return 0;