diff --git a/src/callbacks.c b/src/callbacks.c
index 333f1ee..3feed12 100644
--- a/src/callbacks.c
+++ b/src/callbacks.c
@@ -18,15 +18,11 @@
 #include <stdlib.h>
 #include <libintl.h>
 #include <Desktop.h>
+#include "common.h"
 #include "pdfviewer.h"
 #include "callbacks.h"
 #include "../config.h"
 
-/* constants */
-#ifndef PROGNAME
-# define PROGNAME	"pdfviewer"
-#endif
-
 
 /* public */
 /* functions */
@@ -43,7 +39,7 @@ gboolean on_closex(gpointer data)
 /* on_contents */
 void on_contents(gpointer data)
 {
-	desktop_help_contents(PACKAGE, PROGNAME);
+	desktop_help_contents(PACKAGE, PROGNAME_PDFVIEWER);
 }
 
 
diff --git a/src/common.h b/src/common.h
new file mode 100644
index 0000000..33eefd8
--- /dev/null
+++ b/src/common.h
@@ -0,0 +1,26 @@
+/* $Id$ */
+/* Copyright (c) 2020 Pierre Pronchery <khorben@defora.org> */
+/* This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+
+
+#ifndef PDFVIEWER_COMMON_H
+# define PDFVIEWER_COMMON_H
+
+
+/* constants */
+# ifndef PROGNAME_PDFVIEWER
+#  define PROGNAME_PDFVIEWER	"pdfviewer"
+#endif
+
+#endif /* !PDFVIEWER_COMMON_H */
diff --git a/src/main.c b/src/main.c
index 281a7d9..49e3054 100644
--- a/src/main.c
+++ b/src/main.c
@@ -17,14 +17,12 @@
 #include <stdio.h>
 #include <locale.h>
 #include <libintl.h>
+#include "common.h"
 #include "pdfviewer.h"
 #include "../config.h"
 #define _(string) gettext(string)
 
 /* constants */
-#ifndef PROGNAME
-# define PROGNAME	"pdfviewer"
-#endif
 #ifndef PREFIX
 # define PREFIX		"/usr/local"
 #endif
@@ -46,7 +44,7 @@ static int _usage(void);
 /* error */
 static int _error(char const * message, int ret)
 {
-	fputs(PROGNAME ": ", stderr);
+	fputs(PROGNAME_PDFVIEWER ": ", stderr);
 	perror(message);
 	return ret;
 }
@@ -55,7 +53,7 @@ static int _error(char const * message, int ret)
 /* usage */
 static int _usage(void)
 {
-	fprintf(stderr, _("Usage: %s [file]\n"), PROGNAME);
+	fprintf(stderr, _("Usage: %s [file]\n"), PROGNAME_PDFVIEWER);
 	return 1;
 }
 
diff --git a/src/pdfviewer.c b/src/pdfviewer.c
index daf6205..a32f80f 100644
--- a/src/pdfviewer.c
+++ b/src/pdfviewer.c
@@ -28,16 +28,12 @@ static char const _license[] =
 #include <System.h>
 #include <Desktop.h>
 #include "callbacks.h"
+#include "common.h"
 #include "pdfviewer.h"
 #include "../config.h"
 #define _(string) gettext(string)
 #define N_(string) (string)
 
-/* constants */
-#ifndef PROGNAME
-# define PROGNAME	"pdfviewer"
-#endif
-
 
 /* PDFviewer */
 /* private */
@@ -562,8 +558,8 @@ int pdf_open(PDFviewer * pdfviewer, const char * filename)
 	{
 		if(error != NULL)
 		{
-			fprintf(stderr, PROGNAME ": %s: %s\n", filename,
-					error->message);
+			fprintf(stderr, PROGNAME_PDFVIEWER ": %s: %s\n",
+					filename, error->message);
 			g_error_free(error);
 		}
 		g_free(pdf);
diff --git a/src/project.conf b/src/project.conf
index 79a71a2..6011a67 100644
--- a/src/project.conf
+++ b/src/project.conf
@@ -4,15 +4,20 @@ cflags_force=`pkg-config --cflags libDesktop poppler-glib`
 cflags=-W -Wall -g -O2 -pedantic -fPIE -D_FORTIFY_SOURCE=2 -fstack-protector
 ldflags_force=`pkg-config --libs libDesktop poppler-glib` -lm
 ldflags=-pie -Wl,-z,relro -Wl,-z,now
-dist=Makefile,callbacks.h,pdfviewer.h
+dist=Makefile,callbacks.h,common.h,pdfviewer.h
 
+#targets
 [pdfviewer]
 type=binary
 sources=callbacks.c,pdfviewer.c,main.c
 install=$(BINDIR)
 
+#sources
 [callbacks.c]
-depends=callbacks.h
+depends=callbacks.h,common.h
+
+[main.c]
+depends=common.h,pdfviewer.h
 
 [pdfviewer.c]
-depends=callbacks.h,pdfviewer.h,../config.h
+depends=callbacks.h,common.h,pdfviewer.h,../config.h