diff --git a/ld128/s_nanl.c b/ld128/s_nanl.c
index 66e6fa5..336d8cf 100644
--- a/ld128/s_nanl.c
+++ b/ld128/s_nanl.c
@@ -39,7 +39,7 @@ nanl(const char *s)
 		uint32_t bits[4];
 	} u;
 
-	_scan_nan(u.bits, 4, s);
+	__scan_nan(u.bits, 4, s);
 	u.ieee.bits.exp = 0x7fff;
 	u.ieee.bits.manh |= 1ULL << 47;	/* make it a quiet NaN */
 	return (u.ieee.e);
diff --git a/ld80/s_nanl.c b/ld80/s_nanl.c
index d649968..2b24691 100644
--- a/ld80/s_nanl.c
+++ b/ld80/s_nanl.c
@@ -38,7 +38,7 @@ nanl(const char *s)
 		uint32_t bits[3];
 	} u;
 
-	_scan_nan(u.bits, 3, s);
+	__scan_nan(u.bits, 3, s);
 	u.ieee.bits.exp = 0x7fff;
 	u.ieee.bits.manh |= 0xc0000000;	/* make it a quiet NaN */
 	return (u.ieee.e);
diff --git a/src/math_private.h b/src/math_private.h
index 7bfd76b..daabcea 100644
--- a/src/math_private.h
+++ b/src/math_private.h
@@ -229,7 +229,7 @@ do {								\
 /*
  * Common routine to process the arguments to nan(), nanf(), and nanl().
  */
-void _scan_nan(u_int32_t *__words, int __num_words, const char *__s);
+void __scan_nan(u_int32_t *__words, int __num_words, const char *__s);
 
 #ifdef __GNUCLIKE_ASM
 
diff --git a/src/math_private_openbsd.h b/src/math_private_openbsd.h
index bd0e5b2..8a1774c 100644
--- a/src/math_private_openbsd.h
+++ b/src/math_private_openbsd.h
@@ -205,7 +205,7 @@ do {								\
 /*
  * Common routine to process the arguments to nan(), nanf(), and nanl().
  */
-void _scan_nan(uint32_t *__words, int __num_words, const char *__s);
+void __scan_nan(uint32_t *__words, int __num_words, const char *__s);
 
 /*
  * Functions internal to the math package, yet not static.
diff --git a/src/s_nan.c b/src/s_nan.c
index 6b3631b..95f538e 100644
--- a/src/s_nan.c
+++ b/src/s_nan.c
@@ -62,7 +62,7 @@ static __inline int digittoint(int c) {
  * impossible to use nan(3) portably anyway, so this seems good enough.
  */
 DLLEXPORT void
-_scan_nan(u_int32_t *words, int num_words, const char *s)
+__scan_nan(u_int32_t *words, int num_words, const char *s)
 {
 	int si;		/* index into s */
 	int bitpos;	/* index into words (in bits) */
@@ -97,7 +97,7 @@ nan(const char *s)
 		u_int32_t bits[2];
 	} u;
 
-	_scan_nan(u.bits, 2, s);
+	__scan_nan(u.bits, 2, s);
 #if _BYTE_ORDER == _LITTLE_ENDIAN
 	u.bits[1] |= 0x7ff80000;
 #else
@@ -114,7 +114,7 @@ nanf(const char *s)
 		u_int32_t bits[1];
 	} u;
 
-	_scan_nan(u.bits, 1, s);
+	__scan_nan(u.bits, 1, s);
 	u.bits[0] |= 0x7fc00000;
 	return (u.f);
 }