diff --git a/include/regex.h b/include/regex.h
index 24eca2c297..76fa798861 100644
--- a/include/regex.h
+++ b/include/regex.h
@@ -36,8 +36,24 @@ extern void __re_set_registers
 extern int __regcomp (regex_t *__preg, const char *__pattern, int __cflags);
 libc_hidden_proto (__regcomp)
 
+
+#ifndef __ARG_NELTS
+# ifdef __ARG_NELTS
+/* Same as the corresponding cdefs.h macro.  Defined for builds with
+   no cdefs.h.  */
+#  define __ARG_NELTS(arg) __ARG_NELTS (arg)
+# elif (defined __STDC_VERSION__ && 199901L <= __STDC_VERSION__ \
+        && !defined __STDC_NO_VLA__)
+#  define __ARG_NELTS(n) n
+# else
+#  define __ARG_NELTS(n)
+# endif
+#endif
+
 extern int __regexec (const regex_t *__preg, const char *__string,
-		      size_t __nmatch, regmatch_t __pmatch[], int __eflags);
+		      size_t __nmatch,
+		      regmatch_t __pmatch[__ARG_NELTS (__nmatch)],
+		      int __eflags);
 libc_hidden_proto (__regexec)
 
 extern size_t __regerror (int __errcode, const regex_t *__preg,
diff --git a/misc/sys/cdefs.h b/misc/sys/cdefs.h
index e490fc1aeb..64e46df190 100644
--- a/misc/sys/cdefs.h
+++ b/misc/sys/cdefs.h
@@ -632,4 +632,17 @@ _Static_assert (0, "IEEE 128-bits long double requires redirection on this platf
 # define __attribute_returns_twice__ /* Ignore.  */
 #endif
 
+#ifndef __ARG_NELTS
+# ifdef __ARG_NELTS
+/* Used to specify a variable bound in a declaration of a function
+   VLA-like parameter, as in 'int f (int n, int[__ARG_NELTS (n)]);'  */
+#  define __ARG_NELTS(arg) __ARG_NELTS (arg)
+# elif (defined __STDC_VERSION__ && 199901L <= __STDC_VERSION__ \
+        && !defined __STDC_NO_VLA__)
+#  define __ARG_NELTS(n) n
+# else
+#  define __ARG_NELTS(n)
+# endif
+#endif
+
 #endif	 /* sys/cdefs.h */
diff --git a/posix/regex.h b/posix/regex.h
index 14fb1d8364..5b44f8e52b 100644
--- a/posix/regex.h
+++ b/posix/regex.h
@@ -654,9 +654,8 @@ extern int regcomp (regex_t *_Restrict_ __preg,
 
 extern int regexec (const regex_t *_Restrict_ __preg,
 		    const char *_Restrict_ __String, size_t __nmatch,
-		    regmatch_t __pmatch[_Restrict_arr_],
-		    int __eflags)
-    __attr_access ((__write_only__, 4, 3));
+		    regmatch_t __pmatch[_Restrict_arr_ __ARG_NELTS (__nmatch)],
+		    int __eflags);
 
 extern size_t regerror (int __errcode, const regex_t *_Restrict_ __preg,
 			char *_Restrict_ __errbuf, size_t __errbuf_size)
diff --git a/posix/regexec.c b/posix/regexec.c
index f7b4f9cfc3..bec2fdfe39 100644
--- a/posix/regexec.c
+++ b/posix/regexec.c
@@ -190,7 +190,7 @@ static reg_errcode_t extend_buffers (re_match_context_t *mctx, int min_len);
 
 int
 regexec (const regex_t *__restrict preg, const char *__restrict string,
-	 size_t nmatch, regmatch_t pmatch[], int eflags)
+	 size_t nmatch, regmatch_t pmatch[__ARG_NELTS (nmatch)], int eflags)
 {
   reg_errcode_t err;
   Idx start, length;