I hope this would be useful to convert error codes:
<?php
$curl_errno = array(
1 => "CURLE_UNSUPPORTED_PROTOCOL",
2 => "CURLE_FAILED_INIT",
3 => "CURLE_URL_MALFORMAT",
4 => "CURLE_URL_MALFORMAT_USER",
5 => "CURLE_COULDNT_RESOLVE_PROXY",
6 => "CURLE_COULDNT_RESOLVE_HOST",
7 => "CURLE_COULDNT_CONNECT",
8 => "CURLE_FTP_WEIRD_SERVER_REPLY",
9 => "CURLE_FTP_ACCESS_DENIED",
10 => "CURLE_FTP_USER_PASSWORD_INCORRECT",
11 => "CURLE_FTP_WEIRD_PASS_REPLY",
12 => "CURLE_FTP_WEIRD_USER_REPLY",
13 => "CURLE_FTP_WEIRD_PASV_REPLY",
14 => "CURLE_FTP_WEIRD_227_FORMAT",
15 => "CURLE_FTP_CANT_GET_HOST",
16 => "CURLE_FTP_CANT_RECONNECT",
17 => "CURLE_FTP_COULDNT_SET_BINARY",
18 => "CURLE_FTP_PARTIAL_FILE or CURLE_PARTIAL_FILE",
19 => "CURLE_FTP_COULDNT_RETR_FILE",
20 => "CURLE_FTP_WRITE_ERROR",
21 => "CURLE_FTP_QUOTE_ERROR",
22 => "CURLE_HTTP_NOT_FOUND or CURLE_HTTP_RETURNED_ERROR",
23 => "CURLE_WRITE_ERROR",
24 => "CURLE_MALFORMAT_USER",
25 => "CURLE_FTP_COULDNT_STOR_FILE",
26 => "CURLE_READ_ERROR",
27 => "CURLE_OUT_OF_MEMORY",
28 => "CURLE_OPERATION_TIMEDOUT or CURLE_OPERATION_TIMEOUTED",
29 => "CURLE_FTP_COULDNT_SET_ASCII",
30 => "CURLE_FTP_PORT_FAILED",
31 => "CURLE_FTP_COULDNT_USE_REST",
32 => "CURLE_FTP_COULDNT_GET_SIZE",
33 => "CURLE_HTTP_RANGE_ERROR",
34 => "CURLE_HTTP_POST_ERROR",
35 => "CURLE_SSL_CONNECT_ERROR",
36 => "CURLE_BAD_DOWNLOAD_RESUME or CURLE_FTP_BAD_DOWNLOAD_RESUME",
37 => "CURLE_FILE_COULDNT_READ_FILE",
38 => "CURLE_LDAP_CANNOT_BIND",
39 => "CURLE_LDAP_SEARCH_FAILED",
40 => "CURLE_LIBRARY_NOT_FOUND",
41 => "CURLE_FUNCTION_NOT_FOUND",
42 => "CURLE_ABORTED_BY_CALLBACK",
43 => "CURLE_BAD_FUNCTION_ARGUMENT",
44 => "CURLE_BAD_CALLING_ORDER",
45 => "CURLE_HTTP_PORT_FAILED",
46 => "CURLE_BAD_PASSWORD_ENTERED",
47 => "CURLE_TOO_MANY_REDIRECTS",
48 => "CURLE_UNKNOWN_TELNET_OPTION",
49 => "CURLE_TELNET_OPTION_SYNTAX",
50 => "CURLE_OBSOLETE",
51 => "CURLE_SSL_PEER_CERTIFICATE",
52 => "CURLE_GOT_NOTHING",
53 => "CURLE_SSL_ENGINE_NOTFOUND",
54 => "CURLE_SSL_ENGINE_SETFAILED",
55 => "CURLE_SEND_ERROR",
56 => "CURLE_RECV_ERROR",
57 => "CURLE_SHARE_IN_USE",
58 => "CURLE_SSL_CERTPROBLEM",
59 => "CURLE_SSL_CIPHER",
60 => "CURLE_SSL_CACERT",
61 => "CURLE_BAD_CONTENT_ENCODING",
62 => "CURLE_LDAP_INVALID_URL",
63 => "CURLE_FILESIZE_EXCEEDED",
64 => "CURLE_FTP_SSL_FAILED",
79 => "CURLE_SSH"
);
?>
