diff --git a/hyptop/dg_debugfs.h b/hyptop/dg_debugfs.h
index e6944aee..dd1e423f 100644
--- a/hyptop/dg_debugfs.h
+++ b/hyptop/dg_debugfs.h
@@ -16,10 +16,10 @@
 
 #define DBFS_WAIT_TIME_US 10000
 
-extern int dg_debugfs_init(int exit_on_err);
-extern int dg_debugfs_vm_init(void);
-extern int dg_debugfs_lpar_init(void);
-extern int dg_debugfs_open(const char *file);
+int dg_debugfs_init(int exit_on_err);
+int dg_debugfs_vm_init(void);
+int dg_debugfs_lpar_init(void);
+int dg_debugfs_open(const char *file);
 
 /*
  * z/VM diag 0C prototypes
diff --git a/hyptop/helper.h b/hyptop/helper.h
index 43cdb0ff..2a87f7b0 100644
--- a/hyptop/helper.h
+++ b/hyptop/helper.h
@@ -26,23 +26,23 @@
 /*
  * Helper Prototypes
  */
-extern void hyptop_helper_init(void);
-extern char *ht_strstrip(char *str);
-extern char *ht_strdup(const char *str);
-extern void ht_print_head(const char *sys);
-extern void ht_print_help_icon(void);
-extern void ht_ebcdic_to_ascii(char *in, char *out, size_t len);
-extern char *ht_mount_point_get(const char *fs_type);
-extern u64 ht_ext_tod_2_us(void *tod_ext);
-extern void ht_print_time(void);
-extern s64 ht_calculate_smt_util(u64 core_us, u64 thr_us, u64 mgm_us, int thread_per_core);
+void hyptop_helper_init(void);
+char *ht_strstrip(char *str);
+char *ht_strdup(const char *str);
+void ht_print_head(const char *sys);
+void ht_print_help_icon(void);
+void ht_ebcdic_to_ascii(char *in, char *out, size_t len);
+char *ht_mount_point_get(const char *fs_type);
+u64 ht_ext_tod_2_us(void *tod_ext);
+void ht_print_time(void);
+s64 ht_calculate_smt_util(u64 core_us, u64 thr_us, u64 mgm_us, int thread_per_core);
 
 /*
  * Memory alloc functions
  */
-extern void *ht_zalloc(size_t size);
-extern void *ht_alloc(size_t size);
-extern void *ht_realloc(void *ptr, size_t size);
+void *ht_zalloc(size_t size);
+void *ht_alloc(size_t size);
+void *ht_realloc(void *ptr, size_t size);
 static inline void ht_free(void *ptr)
 {
 	free(ptr);
diff --git a/hyptop/hyptop.h b/hyptop/hyptop.h
index bd5b5ba4..4cf927bb 100644
--- a/hyptop/hyptop.h
+++ b/hyptop/hyptop.h
@@ -184,10 +184,10 @@ enum hyptop_win_action {
 	WIN_KEEP,
 };
 
-extern enum hyptop_win_action hyptop_process_input_timeout(void);
-extern enum hyptop_win_action hyptop_process_input(void);
-extern enum hyptop_win_action win_switch(struct hyptop_win *w);
-extern enum hyptop_win_action win_back(void);
+enum hyptop_win_action hyptop_process_input_timeout(void);
+enum hyptop_win_action hyptop_process_input(void);
+enum hyptop_win_action win_switch(struct hyptop_win *w);
+enum hyptop_win_action win_back(void);
 
 struct hyptop_win;
 struct hyptop_win {
@@ -206,25 +206,25 @@ struct hyptop_win {
  * Window sys_list
  */
 extern struct hyptop_win win_sys_list;
-extern void win_sys_list_init(void);
+void win_sys_list_init(void);
 
 /*
  * Window sys
  */
 extern struct hyptop_win win_sys;
-extern void win_sys_set(const char *sys_id);
-extern void win_sys_init(void);
+void win_sys_set(const char *sys_id);
+void win_sys_init(void);
 
 /*
  * Window cpu_types
  */
-extern void win_cpu_types_init(void);
+void win_cpu_types_init(void);
 
 /*
  * Misc functions
  */
-extern void hyptop_update_term(void);
-extern void __noreturn hyptop_exit(int rc);
-extern void hyptop_text_mode(void);
+void hyptop_update_term(void);
+void __noreturn hyptop_exit(int rc);
+void hyptop_text_mode(void);
 
 #endif /* HYPTOP_H */
diff --git a/hyptop/opts.h b/hyptop/opts.h
index 73c5852e..f69a93a8 100644
--- a/hyptop/opts.h
+++ b/hyptop/opts.h
@@ -14,9 +14,9 @@
 
 #include "hyptop.h"
 
-extern void opts_parse(int argc, char *argv[]);
-extern void opts_iterations_next(void);
-extern int opts_sys_specified(struct hyptop_win *win, const char* sys_name);
-extern void opt_verify_systems(void);
+void opts_parse(int argc, char *argv[]);
+void opts_iterations_next(void);
+int opts_sys_specified(struct hyptop_win *win, const char *sys_name);
+void opt_verify_systems(void);
 
 #endif /* OPTS_H */
diff --git a/hyptop/sd.h b/hyptop/sd.h
index fdfda6a6..fc99abb7 100644
--- a/hyptop/sd.h
+++ b/hyptop/sd.h
@@ -308,8 +308,8 @@ struct sd_cpu_item {
 #define sd_cpu_item_type(x) ((x)->type)
 #define sd_cpu_item_table_col(item) (&(item)->table_col)
 
-extern int sd_cpu_item_available(struct sd_cpu_item *item);
-extern int sd_cpu_item_cnt(void);
+int sd_cpu_item_available(struct sd_cpu_item *item);
+int sd_cpu_item_cnt(void);
 
 /*
  * Item access functions
@@ -377,8 +377,8 @@ struct sd_sys_item {
 #define sd_sys_item_table_col(item) (&item->table_col)
 #define sd_sys_item_type(item) (item->type)
 
-extern int sd_sys_item_available(struct sd_sys_item *item);
-extern int sd_sys_item_cnt(void);
+int sd_sys_item_available(struct sd_sys_item *item);
+int sd_sys_item_cnt(void);
 
 /*
  * Item access functions
@@ -520,7 +520,7 @@ static inline s64 l_cpu_info_s64(struct sd_cpu_info *info,
  * Misc
  */
 void sd_update(void);
-extern void sd_init(void);
+void sd_init(void);
 
 static inline u64 l_sub_64(u64 x, u64 y)
 {
diff --git a/hyptop/table.h b/hyptop/table.h
index 78152539..42ef6735 100644
--- a/hyptop/table.h
+++ b/hyptop/table.h
@@ -362,37 +362,37 @@ enum table_scroll_unit {
  */
 extern struct table *table_new(int extra_rows, int sorted, int first_bold,
 			       int with_units);
-extern void table_reset(struct table *t);
-extern void table_rebuild(struct table *t);
-extern void table_finish(struct table *t);
-extern void table_print(struct table *t);
-extern void table_process_input(struct table *t, int c);
+void table_reset(struct table *t);
+void table_rebuild(struct table *t);
+void table_finish(struct table *t);
+void table_print(struct table *t);
+void table_process_input(struct table *t, int c);
 
-extern void table_col_unit_next(struct table *t, char hotkey);
-extern void table_col_unit_prev(struct table *t, char hotkey);
-extern int table_col_unit_set(struct table *t, char hotkey, const char *unit);
-extern void table_col_add(struct table *t, struct table_col *col);
-extern int table_col_select(struct table *t, char hotkey);
-extern void table_col_select_next(struct table *t);
-extern void table_col_select_prev(struct table *t);
-extern void table_col_enable_toggle(struct table *t, char hotkey);
+void table_col_unit_next(struct table *t, char hotkey);
+void table_col_unit_prev(struct table *t, char hotkey);
+int table_col_unit_set(struct table *t, char hotkey, const char *unit);
+void table_col_add(struct table *t, struct table_col *col);
+int table_col_select(struct table *t, char hotkey);
+void table_col_select_next(struct table *t);
+void table_col_select_prev(struct table *t);
+void table_col_enable_toggle(struct table *t, char hotkey);
 
-extern void table_row_del_all(struct table *t);
-extern void table_row_add(struct table *t, struct table_row *row);
-extern void table_row_mark(struct table *t, struct table_row *row);
-extern void table_row_mark_del_all(struct table *t);
-extern void table_row_mark_toggle(struct table *t, struct table_row *row);
-extern void table_row_mark_toggle_by_key(struct table *t, const char *mark_key);
-extern void table_row_select_down(struct table *t, enum table_scroll_unit unit);
-extern void table_row_select_up(struct table *t, enum table_scroll_unit unit);
-extern void table_row_select_key_get(struct table *t, char str[TABLE_STR_MAX]);
-extern struct table_row *table_row_alloc(struct table *t);
+void table_row_del_all(struct table *t);
+void table_row_add(struct table *t, struct table_row *row);
+void table_row_mark(struct table *t, struct table_row *row);
+void table_row_mark_del_all(struct table *t);
+void table_row_mark_toggle(struct table *t, struct table_row *row);
+void table_row_mark_toggle_by_key(struct table *t, const char *mark_key);
+void table_row_select_down(struct table *t, enum table_scroll_unit unit);
+void table_row_select_up(struct table *t, enum table_scroll_unit unit);
+void table_row_select_key_get(struct table *t, char str[TABLE_STR_MAX]);
+struct table_row *table_row_alloc(struct table *t);
 
-extern void table_scroll_down(struct table *t, enum table_scroll_unit unit);
-extern void table_scroll_up(struct table *t, enum table_scroll_unit unit);
+void table_scroll_down(struct table *t, enum table_scroll_unit unit);
+void table_scroll_up(struct table *t, enum table_scroll_unit unit);
 
-extern void table_fmt_start(void);
-extern void table_fmt_end(void);
+void table_fmt_start(void);
+void table_fmt_end(void);
 
 /*
  * Entry add functions
diff --git a/hyptop/win_cpu_types.h b/hyptop/win_cpu_types.h
index a7f71a33..d8886331 100644
--- a/hyptop/win_cpu_types.h
+++ b/hyptop/win_cpu_types.h
@@ -23,6 +23,6 @@ struct win_cpu_types {
 	struct hyptop_win	*win_help;
 };
 
-extern struct hyptop_win *win_cpu_types_new(void);
+struct hyptop_win *win_cpu_types_new(void);
 
 #endif /* WIN_CPU_TYPES_H */