diff --git a/include/dialogs/filebrowser.h b/include/dialogs/filebrowser.h
index ea440a71..8816bdb3 100644
--- a/include/dialogs/filebrowser.h
+++ b/include/dialogs/filebrowser.h
@@ -38,7 +38,20 @@
 /** #Mode object representing the run dialog. */
 extern Mode file_browser_mode;
 
+/**
+ * Create a new filebrowser.
+ * @returns a new filebrowser structure.
+ */
 Mode *create_new_file_browser ( void );
+/**
+ * @param sw Mode object.
+ * @param mretv return value passed in.
+ * @param input The user input string.
+ * @param selected_list The user selected line.
+ * @param path The full path as output.
+ *
+ * @returns the state the user selected.
+ */
 ModeMode file_browser_mode_completer ( Mode *sw, int mretv, char **input, unsigned int selected_line, char **path );
 /**@}*/
 #endif // ROFI_DIALOG_FILE_BROWSER_H
diff --git a/include/rofi-icon-fetcher.h b/include/rofi-icon-fetcher.h
index 19a46241..fed9c588 100644
--- a/include/rofi-icon-fetcher.h
+++ b/include/rofi-icon-fetcher.h
@@ -45,6 +45,13 @@ uint32_t rofi_icon_fetcher_query ( const char *name, const int size );
  */
 cairo_surface_t * rofi_icon_fetcher_get ( const uint32_t uid );
 
+/**
+ * @param path the image path to check.
+ *
+ * Checks if a file is a supported image. (by looking at extension).
+ *
+ * @returns true if image, false otherwise.
+ */
 gboolean rofi_icon_fetcher_file_is_image ( const char * const path );
 /** @} */
 #endif // ROFI_ICON_FETCHER_H
diff --git a/include/theme.h b/include/theme.h
index f50f892e..151446bc 100644
--- a/include/theme.h
+++ b/include/theme.h
@@ -386,6 +386,12 @@ void rofi_theme_parse_merge_widgets ( ThemeWidget *parent, ThemeWidget *child );
  * Returns the media type described by type.
  */
 ThemeMediaType rofi_theme_parse_media_type ( const char *type );
+
+/**
+ * @param distance The distance object to copy.
+ *
+ * @returns a copy of the distance.
+ */
 RofiDistance rofi_theme_property_copy_distance  ( RofiDistance const distance );
 
 /**
diff --git a/include/xcb.h b/include/xcb.h
index 77962e51..b342e94e 100644
--- a/include/xcb.h
+++ b/include/xcb.h
@@ -127,7 +127,16 @@ typedef struct _workarea
  */
 int monitor_active ( workarea *mon );
 
+/**
+ * @param w rofis window
+ *
+ * Stores old input focus for reverting and set focus to rofi.
+ */
 void rofi_xcb_set_input_focus(xcb_window_t w);
+
+/**
+ * IF set, revert the focus back to the original applications.
+ */
 void rofi_xcb_revert_input_focus(void);
 
 /**
@@ -194,5 +203,13 @@ extern WindowManagerQuirk current_window_manager;
  * @returns NULL if window was not found, or unmapped, otherwise returns a cairo_surface.
  */
 cairo_surface_t *x11_helper_get_screenshot_surface_window ( xcb_window_t window, int size );
+
+/**
+ * @param surface
+ * @param radius
+ * @param deviation
+ *
+ * Blur the content of the surface with radius and deviation.
+ */
 void cairo_image_surface_blur(cairo_surface_t* surface, double radius, double deviation);
 #endif
diff --git a/source/dialogs/filebrowser.c b/source/dialogs/filebrowser.c
index 568eef69..d53068ed 100644
--- a/source/dialogs/filebrowser.c
+++ b/source/dialogs/filebrowser.c
@@ -58,6 +58,7 @@ enum FBFileType
     RFILE,
     NUM_FILE_TYPES,
 };
+/** Icons to use for the file type  */
 const char *icon_name[NUM_FILE_TYPES] =
 {
     "go-up",
diff --git a/source/rofi-icon-fetcher.c b/source/rofi-icon-fetcher.c
index cfe9d747..99fe3180 100644
--- a/source/rofi-icon-fetcher.c
+++ b/source/rofi-icon-fetcher.c
@@ -163,14 +163,22 @@ void rofi_icon_fetcher_destroy ( void )
  *     Copyright (C) 2011-2018 Red Hat, Inc.
  */
 #if G_BYTE_ORDER == G_LITTLE_ENDIAN
+/** Location of red byte */
 #define RED_BYTE      2
+/** Location of green byte */
 #define GREEN_BYTE    1
+/** Location of blue byte */
 #define BLUE_BYTE     0
+/** Location of alpha byte */
 #define ALPHA_BYTE    3
 #else
+/** Location of red byte */
 #define RED_BYTE      1
+/** Location of green byte */
 #define GREEN_BYTE    2
+/** Location of blue byte */
 #define BLUE_BYTE     3
+/** Location of alpha byte */
 #define ALPHA_BYTE    0
 #endif
 
diff --git a/source/rofi.c b/source/rofi.c
index 8c5cca77..c9dad4d3 100644
--- a/source/rofi.c
+++ b/source/rofi.c
@@ -119,6 +119,7 @@ static int      dmenu_mode = FALSE;
 /** Rofi's return code */
 int             return_code = EXIT_SUCCESS;
 
+/** Flag indicating we are using old config format. */
 static gboolean old_config_format = FALSE;
 
 void process_result ( RofiViewState *state );
diff --git a/source/view.c b/source/view.c
index 5d94f89d..1b2edd76 100644
--- a/source/view.c
+++ b/source/view.c
@@ -227,11 +227,19 @@ void rofi_capture_screenshot ( void )
  * Code used for benchmarking drawing the gui, this will keep updating the UI as fast as possible.
  */
 gboolean do_bench = TRUE;
-struct
+
+/**
+ * Internal structure that hold benchmarking information.
+ */
+static struct
 {
+    /** timer used for timestamping. */
     GTimer   *time;
+    /** number of draws done. */
     uint64_t draws;
+    /** previous timestamp */
     double   last_ts;
+    /** minimum draw time. */
     double   min;
 } BenchMark = {
     .time    = NULL,
diff --git a/source/widgets/textbox.c b/source/widgets/textbox.c
index a5112755..cd58ad00 100644
--- a/source/widgets/textbox.c
+++ b/source/widgets/textbox.c
@@ -55,8 +55,8 @@ static PangoContext     *p_context = NULL;
 /** The pango font metrics */
 static PangoFontMetrics *p_metrics = NULL;
 
-/* Default tbfc */
-TBFontConfig *tbfc_default = NULL;
+/** Default tbfc */
+static TBFontConfig *tbfc_default = NULL;
 
 /** HashMap of previously parsed font descriptions. */
 static GHashTable *tbfc_cache = NULL;
diff --git a/source/widgets/widget.c b/source/widgets/widget.c
index 1a309b00..99bb8736 100644
--- a/source/widgets/widget.c
+++ b/source/widgets/widget.c
@@ -33,6 +33,7 @@
 
 /** Default padding. */
 #define WIDGET_DEFAULT_PADDING    0
+/** macro for initializing the padding struction. */
 #define WIDGET_PADDING_INIT       { { WIDGET_DEFAULT_PADDING, ROFI_PU_PX, ROFI_DISTANCE_MODIFIER_NONE, NULL, NULL }, ROFI_HL_SOLID }
 
 /* Corner radius - tl, tr, br, bl */