doc: clarify napi_get_value_string_* for bufsize 0

PR-URL: #58158
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Chengzhong Wu <[email protected]>
Reviewed-By: Michael Dawson <[email protected]>

Author: tniessen

doc/api/n-api.md

@@ -3683,6 +3683,8 @@ napi_status napi_get_value_string_latin1(napi_env env,
   is returned in `result`.
 * `[in] bufsize`: Size of the destination buffer. When this value is
   insufficient, the returned string is truncated and null-terminated.
+  If this value is zero, then the string is not returned and no changes are done
+  to the buffer.
 * `[out] result`: Number of bytes copied into the buffer, excluding the null
   terminator.
 
@@ -3714,6 +3716,8 @@ napi_status napi_get_value_string_utf8(napi_env env,
   returned in `result`.
 * `[in] bufsize`: Size of the destination buffer. When this value is
   insufficient, the returned string is truncated and null-terminated.
+  If this value is zero, then the string is not returned and no changes are done
+  to the buffer.
 * `[out] result`: Number of bytes copied into the buffer, excluding the null
   terminator.
 
@@ -3744,6 +3748,8 @@ napi_status napi_get_value_string_utf16(napi_env env,
   null terminator is returned.
 * `[in] bufsize`: Size of the destination buffer. When this value is
   insufficient, the returned string is truncated and null-terminated.
+  If this value is zero, then the string is not returned and no changes are done
+  to the buffer.
 * `[out] result`: Number of 2-byte code units copied into the buffer, excluding
   the null terminator.