diff --git a/doc/crypto/ERR_error_string.pod b/doc/crypto/ERR_error_string.pod
index e01beb817..cdfa7fe1f 100644
--- a/doc/crypto/ERR_error_string.pod
+++ b/doc/crypto/ERR_error_string.pod
@@ -11,7 +11,7 @@ error message
  #include <openssl/err.h>
 
  char *ERR_error_string(unsigned long e, char *buf);
- char *ERR_error_string_n(unsigned long e, char *buf, size_t len);
+ void ERR_error_string_n(unsigned long e, char *buf, size_t len);
 
  const char *ERR_lib_error_string(unsigned long e);
  const char *ERR_func_error_string(unsigned long e);