Add strnlen

2 files changed, 11 insertions, 1 deletions

diff --git a/libc/string/Makefile b/libc/string/Makefile
index 02a69dfbf..6823f2759 100644
--- a/libc/string/Makefile
+++ b/libc/string/Makefile
@@ -27,7 +27,7 @@ LIBC=$(TOPDIR)libc.a
 MSRC=string.c
 MOBJ=strlen.o strcat.o strcpy.o strchr.o strcmp.o strncat.o strncpy.o \
 	strncmp.o strrchr.o strdup.o memcpy.o memccpy.o memset.o \
-	memmove.o memcmp.o memchr.o ffs.o
+	memmove.o memcmp.o memchr.o ffs.o strnlen.o
 
 MSRC1=index.c
 MOBJ1=index.o rindex.o
diff --git a/libc/string/string.c b/libc/string/string.c
index f77cf4c69..29ac83a24 100644
--- a/libc/string/string.c
+++ b/libc/string/string.c
@@ -23,6 +23,16 @@ size_t strlen(const char *str)
 }
 #endif
 
+/********************** Function strnlen ************************************/
+
+#ifdef L_strnlen
+size_t strnlen (const char *string, size_t maxlen)
+{
+	const char *end = memchr (string, '\0', maxlen);
+	return end ? end - string : maxlen;
+}
+#endif
+
 /********************** Function strcat ************************************/
 
 #ifdef L_strcat