libcurl-errors

libcurl-errors - error codes in libcurl

This man page includes most, if not all, available error codes in libcurl. Why they occur and possibly what you can do to fix the problem.

Almost all "easy" interface functions return a CURLcode error code. No matter what, using the curl_easy_setopt(3) option CURLOPT_ERRORBUFFER is a good idea as it will give you a human readable error string that may offer more details about the error cause than just the error code does. curl_easy_strerror(3) can be called to get an error string from a given CURLcode number. CURLcode is one of the following:

"CURLE_OK All fine. Proceed as usual.

"CURLE_UNSUPPORTED_PROTOCOL The URL you passed to libcurl used a protocol that this libcurl does not support. The support might be a compile-time option that you didn't use, it can be a misspelled protocol string or just a protocol libcurl has no code for.

"CURLE_FAILED_INIT Very early initialization code failed. This is likely to be an internal error or problem.

"CURLE_URL_MALFORMAT The URL was not properly formatted.

"CURLE_URL_MALFORMAT_USER This is never returned by current libcurl.

"CURLE_COULDNT_RESOLVE_PROXY Couldn't resolve proxy. The given proxy host could not be resolved.

"CURLE_COULDNT_RESOLVE_HOST Couldn't resolve host. The given remote host was not resolved.

"CURLE_COULDNT_CONNECT Failed to connect() to host or proxy.

"CURLE_FTP_WEIRD_SERVER_REPLY After connecting to an FTP server, libcurl expects to get a certain reply back. This error code implies that it got a strange or bad reply. The given remote server is probably not an OK FTP server.

"CURLE_FTP_ACCESS_DENIED We were denied access when trying to login to an FTP server or when trying to change working directory to the one given in the URL.

"CURLE_FTP_USER_PASSWORD_INCORRECT This is never returned by current libcurl.

"CURLE_FTP_WEIRD_PASS_REPLY After having sent the FTP password to the server, libcurl expects a proper reply. This error code indicates that an unexpected code was returned.

"CURLE_FTP_WEIRD_USER_REPLY After having sent user name to the FTP server, libcurl expects a proper reply. This error code indicates that an unexpected code was returned.

"CURLE_FTP_WEIRD_PASV_REPLY libcurl failed to get a sensible result back from the server as a response to either a PASV or a EPSV command. The server is flawed.

"CURLE_FTP_WEIRD_227_FORMAT FTP servers return a 227-line as a response to a PASV command. If libcurl fails to parse that line, this return code is passed back.

"CURLE_FTP_CANT_GET_HOST An internal failure to lookup the host used for the new connection.

"CURLE_FTP_CANT_RECONNECT A bad return code on either PASV or EPSV was sent by the FTP server, preventing libcurl from being able to continue.

"CURLE_FTP_COULDNT_SET_BINARY Received an error when trying to set the transfer mode to binary.

"CURLE_PARTIAL_FILE A file transfer was shorter or larger than expected. This happens when the server first reports an expected transfer size, and then delivers data that doesn't match the previously given size.

"CURLE_FTP_COULDNT_RETR_FILE This was either a weird reply to a 'RETR' command or a zero byte transfer complete.

"CURLE_FTP_WRITE_ERROR After a completed file transfer, the FTP server did not respond a proper \"transfer successful\" code.

"CURLE_FTP_QUOTE_ERROR When sending custom "QUOTE" commands to the remote server, one of the commands returned an error code that was 400 or higher.

"CURLE_HTTP_RETURNED_ERROR This is returned if CURLOPT_FAILONERROR is set TRUE and the HTTP server returns an error code that is >= 400.

"CURLE_WRITE_ERROR An error occurred when writing received data to a local file, or an error was returned to libcurl from a write callback.

"CURLE_MALFORMAT_USER This is never returned by current libcurl.

"CURLE_UPLOAD_FAILED Failed starting the upload. For FTP, the server typcially denied the STOR command. The error buffer usually contains the server's explanation to this. (This error code was formerly known as CURLE_FTP_COULDNT_STOR_FILE.)

"CURLE_READ_ERROR There was a problem reading a local file or an error returned by the read callback.

"CURLE_OUT_OF_MEMORY Out of memory. A memory allocation request failed. This is serious badness and things are severely screwed up if this ever occur.

"CURLE_OPERATION_TIMEOUTED Operation timeout. The specified time-out period was reached according to the conditions.

"CURLE_FTP_COULDNT_SET_ASCII libcurl failed to set ASCII transfer type (TYPE A).

"CURLE_FTP_PORT_FAILED The FTP PORT command returned error. This mostly happen when you haven't specified a good enough address for libcurl to use. See CURLOPT_FTPPORT.

"CURLE_FTP_COULDNT_USE_REST The FTP REST command returned error. This should never happen if the server is sane.

"CURLE_FTP_COULDNT_GET_SIZE The FTP SIZE command returned error. SIZE is not a kosher FTP command, it is an extension and not all servers support it. This is not a surprising error.

"CURLE_HTTP_RANGE_ERROR The HTTP server does not support or accept range requests.

"CURLE_HTTP_POST_ERROR This is an odd error that mainly occurs due to internal confusion.

"CURLE_SSL_CONNECT_ERROR A problem occurred somewhere in the SSL/TLS handshake. You really want the error buffer and read the message there as it pinpoints the problem slightly more. Could be certificates (file formats, paths, permissions), passwords, and others.

"CURLE_FTP_BAD_DOWNLOAD_RESUME Attempting FTP resume beyond file size.

"CURLE_FILE_COULDNT_READ_FILE A file given with FILE:// couldn't be opened. Most likely because the file path doesn't identify an existing file. Did you check file permissions?

"CURLE_LDAP_CANNOT_BIND LDAP cannot bind. LDAP bind operation failed.

"CURLE_LDAP_SEARCH_FAILED LDAP search failed.

"CURLE_LIBRARY_NOT_FOUND Library not found. The LDAP library was not found.

"CURLE_FUNCTION_NOT_FOUND Function not found. A required LDAP function was not found.

"CURLE_ABORTED_BY_CALLBACK Aborted by callback. A callback returned "abort" to libcurl.

"CURLE_BAD_FUNCTION_ARGUMENT Internal error. A function was called with a bad parameter.

"CURLE_BAD_CALLING_ORDER This is never returned by current libcurl.

"CURLE_HTTP_PORT_FAILED Interface error. A specified outgoing interface could not be used. Set which interface to use for outgoing connections' source IP address with CURLOPT_INTERFACE.

"CURLE_BAD_PASSWORD_ENTERED This is never returned by current libcurl.

"CURLE_TOO_MANY_REDIRECTS Too many redirects. When following redirects, libcurl hit the maximum amount. Set your limit with CURLOPT_MAXREDIRS.

"CURLE_UNKNOWN_TELNET_OPTION An option set with CURLOPT_TELNETOPTIONS was not recognized/known. Refer to the appropriate documentation.

"CURLE_TELNET_OPTION_SYNTAX A telnet option string was Illegally formatted.

"CURLE_OBSOLETE This is not an error. This used to be another error code in an old libcurl version and is currently unused.

"CURLE_SSL_PEER_CERTIFICATE The remote server's SSL certificate was deemed not OK.

"CURLE_GOT_NOTHING Nothing was returned from the server, and under the circumstances, getting nothing is considered an error.

"CURLE_SSL_ENGINE_NOTFOUND The specified crypto engine wasn't found.

"CURLE_SSL_ENGINE_SETFAILED Failed setting the selected SSL crypto engine as default!

"CURLE_SEND_ERROR Failed sending network data.

"CURLE_RECV_ERROR Failure with receiving network data.

"CURLE_SHARE_IN_USE Share is in use

"CURLE_SSL_CERTPROBLEM problem with the local client certificate

"CURLE_SSL_CIPHER couldn't use specified cipher

"CURLE_SSL_CACERT peer certificate cannot be authenticated with known CA certificates

"CURLE_BAD_CONTENT_ENCODING Unrecognized transfer encoding

"CURLE_LDAP_INVALID_URL Invalid LDAP URL

"CURLE_FILESIZE_EXCEEDED Maximum file size exceeded

"CURLE_FTP_SSL_FAILED Requested FTP SSL level failed

"CURLE_SEND_FAIL_REWIND When doing a send operation curl had to rewind the data to retransmit, but the rewinding operation failed

"CURLE_SSL_ENGINE_INITFAILED Initiating the SSL Engine failed

"CURLE_LOGIN_DENIED The remote server denied curl to login (Added in 7.13.1)

"CURLE_TFTP_NOTFOUND File not found on TFTP server

"CURLE_TFTP_PERM Permission problem on TFTP server

"CURLE_TFTP_DISKFULL Out of disk space on TFTP server

"CURLE_TFTP_ILLEGAL Illegal TFTP operation

"CURLE_TFTP_UNKNOWNID Unknown TFTP transfer ID

"CURLE_TFTP_EXISTS TFTP File already exists

"CURLE_TFTP_NOSUCHUSER No such TFTP user

"CURLE_CONV_FAILED Character conversion failed

"CURLE_CONV_REQD Caller must register conversion callbacks

"CURLE_SSL_CACERT_BADFILE Problem with reading the SSL CA cert (path? access rights?)

This is the generic return code used by functions in the libcurl multi interface. Also consider curl_multi_strerror(3).

"CURLM_CALL_MULTI_PERFORM This is not really an error. It means you should call curl_multi_perform(3) again without doing select() or similar in between.

"CURLM_OK Things are fine.

"CURLM_BAD_HANDLE The passed-in handle is not a valid CURLM handle.

"CURLM_BAD_EASY_HANDLE An easy handle was not good/valid. It could mean that it isn't an easy handle at all, or possibly that the handle already is in used by this or another multi handle.

"CURLM_OUT_OF_MEMORY You are doomed.

"CURLM_INTERNAL_ERROR This can only be returned if libcurl bugs. Please report it to us!

"CURLM_BAD_SOCKET The passed-in socket is not a valid one that libcurl already knows about. (Added in 7.15.4)

The "share" interface will return a CURLSHcode to indicate when an error has occurred. Also consider curl_share_strerror(3).

"CURLSHE_OK All fine. Proceed as usual.

"CURLSHE_BAD_OPTION An invalid option was passed to the function.

"CURLSHE_IN_USE The share object is currently in use.

"CURLSHE_INVALID An invalid share object was passed to the function.