diff --git a/lib/libc/string/memchr.c b/lib/libc/string/memchr.c
index 47d37db16be..6d7c2fd94e7 100644
--- a/lib/libc/string/memchr.c
+++ b/lib/libc/string/memchr.c
@@ -39,7 +39,7 @@ __FBSDID("$FreeBSD$");
 #include <string.h>
 
 void *
-memchr(const void *s, unsigned char c, size_t n)
+memchr(const void *s, int c, size_t n)
 {
 	if (n != 0) {
 		const unsigned char *p = s;
diff --git a/lib/libc/string/strmode.c b/lib/libc/string/strmode.c
index 855e1b5acde..57295d7c5b4 100644
--- a/lib/libc/string/strmode.c
+++ b/lib/libc/string/strmode.c
@@ -38,7 +38,7 @@ __FBSDID("$FreeBSD$");
 #include <string.h>
 
 void
-strmode(mode_t mode, char *p)
+strmode(/* mode_t */ int mode, char *p)
 {
 	 /* print type */
 	switch (mode & S_IFMT) {
diff --git a/lib/libc/string/wmemset.c b/lib/libc/string/wmemset.c
index 362bdf23037..0e96356ec00 100644
--- a/lib/libc/string/wmemset.c
+++ b/lib/libc/string/wmemset.c
@@ -37,7 +37,7 @@ __FBSDID("$FreeBSD$");
 #include <wchar.h>
 
 wchar_t	*
-wmemset(wchar_t *s, wchar_t *c, size_t n)
+wmemset(wchar_t *s, wchar_t c, size_t n)
 {
 	size_t i;
 	wchar_t *p;