diff --git a/include/time.h b/include/time.h
index 99bb1c8e3..642d68c4e 100644
--- a/include/time.h
+++ b/include/time.h
@@ -89,8 +89,8 @@ struct tm {
 #  define CLOCKS_PER_SEC        10
 #elif defined(__ATARI__) || defined (__LYNX__)
 /* Read the clock rate at runtime */
-clock_t _clocks_per_sec (void);
-#  define CLOCKS_PER_SEC        _clocks_per_sec()
+clock_t __clocks_per_sec (void);
+#  define CLOCKS_PER_SEC        __clocks_per_sec()
 #endif
 #define CLOCK_REALTIME          0
 
diff --git a/libsrc/atari/clock.s b/libsrc/atari/clock.s
index 853870520..42809c4a4 100644
--- a/libsrc/atari/clock.s
+++ b/libsrc/atari/clock.s
@@ -3,10 +3,10 @@
 ; originally by Ullrich von Bassewitz and Sidney Cadot
 ;
 ; clock_t clock (void);
-; clock_t _clocks_per_sec (void);
+; clock_t __clocks_per_sec (void);
 ;
 
-        .export         _clock, __clocks_per_sec
+        .export         _clock, ___clocks_per_sec
         .importzp       sreg
 
         .include        "atari.inc"
@@ -28,7 +28,7 @@
 .endproc
 
 
-.proc   __clocks_per_sec
+.proc   ___clocks_per_sec
 
         ldx     #$00            ; Clear byte 1 of return value
         stx     sreg            ; Clear byte 2 of return value
diff --git a/libsrc/atari7800/clocks_per_sec.s b/libsrc/atari7800/clocks_per_sec.s
index e2c7d9d8d..d9179448f 100644
--- a/libsrc/atari7800/clocks_per_sec.s
+++ b/libsrc/atari7800/clocks_per_sec.s
@@ -1,10 +1,10 @@
 ;
 ; 2022-03-15, Karri Kaksonen
 ;
-; clock_t _clocks_per_sec (void);
+; clock_t __clocks_per_sec (void);
 ;
 
-        .export         __clocks_per_sec
+        .export         ___clocks_per_sec
 
         .import         sreg: zp
         .import         _paldetected
@@ -17,7 +17,7 @@
 ;-----------------------------------------------------------------------------
 ; Return the number of clock ticks in one second.
 ;
-        .proc   __clocks_per_sec
+        .proc   ___clocks_per_sec
 
         lda     #0
         tax
diff --git a/libsrc/lynx/clock.s b/libsrc/lynx/clock.s
index e29799df6..d881e5a67 100644
--- a/libsrc/lynx/clock.s
+++ b/libsrc/lynx/clock.s
@@ -3,13 +3,13 @@
 ; 2012-02-06, Greg King
 ;
 ; clock_t clock (void);
-; clock_t _clocks_per_sec (void);
+; clock_t __clocks_per_sec (void);
 ;
 ; clocks_per_sec()'s test-values are based on the numbers in "set_tv.s".
 ; If you change the numbers there, then change them here, too.
 ;
 
-        .export         _clock, __clocks_per_sec, clock_count
+        .export         _clock, ___clocks_per_sec, clock_count
         .interruptor    update_clock, 2 ; (low priority)
         .constructor    init_clock
 
@@ -38,7 +38,7 @@
 ;-----------------------------------------------------------------------------
 ; Return the number of clock ticks in one second.
 ;
-__clocks_per_sec:
+___clocks_per_sec:
         ldx     #$00            ; >50, >60, >75
         ldy     PBKUP
         lda     #<75