diff --git a/content/capi/writing-c-functions.mdz b/content/capi/writing-c-functions.mdz
index 270c71d3..0c3dacc7 100644
--- a/content/capi/writing-c-functions.mdz
+++ b/content/capi/writing-c-functions.mdz
@@ -69,6 +69,7 @@ JanetTable *janet_gettable(const Janet *argv, int32_t n);
 const JanetKV *janet_getstruct(const Janet *argv, int32_t n);
 const uint8_t *janet_getstring(const Janet *argv, int32_t n);
 const char *janet_getcstring(const Janet *argv, int32_t n);
+const char *janet_getcbytes(const Janet *argv, int32_t n);
 const uint8_t *janet_getsymbol(const Janet *argv, int32_t n);
 const uint8_t *janet_getkeyword(const Janet *argv, int32_t n);
 JanetBuffer *janet_getbuffer(const Janet *argv, int32_t n);
@@ -104,6 +105,7 @@ const Janet *janet_opttuple(const Janet *argv, int32_t argc, int32_t n, const Ja
 const JanetKV *janet_optstruct(const Janet *argv, int32_t argc, int32_t n, const JanetKV *dflt);
 const uint8_t *janet_optstring(const Janet *argv, int32_t argc, int32_t n, const uint8_t *dflt);
 const char *janet_optcstring(const Janet *argv, int32_t argc, int32_t n, const char *dflt);
+const char *janet_optcbytes(const Janet *argv, int32_t argc, int32_t n, const char *dflt);
 const uint8_t *janet_optsymbol(const Janet *argv, int32_t argc, int32_t n, const uint8_t *dflt);
 const uint8_t *janet_optkeyword(const Janet *argv, int32_t argc, int32_t n, const uint8_t *dflt);
 JanetFiber *janet_optfiber(const Janet *argv, int32_t argc, int32_t n, JanetFiber *dflt);