CURLOPT_PREREQFUNCTION.md: add result code on failure

Closes #15542

diff --git a/docs/libcurl/opts/CURLOPT_PREREQFUNCTION.md b/docs/libcurl/opts/CURLOPT_PREREQFUNCTION.md
index 8024a9a897e47ad6930135600bb8736fc8e34feb..bb9bb822e98e0fece5d6b2950d5cffe9d20c9dac 100644 (file)
--- a/docs/libcurl/opts/CURLOPT_PREREQFUNCTION.md
+++ b/docs/libcurl/opts/CURLOPT_PREREQFUNCTION.md
@@ -51,7 +51,8 @@ This function may be called multiple times if redirections are enabled and are
 being followed (see CURLOPT_FOLLOWLOCATION(3)).
 
 The callback function must return *CURL_PREREQFUNC_OK* on success, or
-*CURL_PREREQFUNC_ABORT* to cause the transfer to fail.
+*CURL_PREREQFUNC_ABORT* to cause the transfer to fail with result
+*CURLE_ABORTED_BY_CALLBACK*.
 
 This function is passed the following arguments: