libcurl-errors(3) libcurl errors libcurl-errors(3)
NAME
libcurl-errors - error codes in libcurl
DESCRIPTION
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 prob-
lem are also included.
CURLcode
Almost all "easy" interface functions return a CURLcode error code. No
matter what, using the curl_easy_setopt(3) option CURLOPT_ERROR-
BUFFER(3) is a good idea as it will give you a human readable error
string that may offer more details about the cause of the error than
just the error code. curl_easy_strerror(3) can be called to get an er-
ror string from a given CURLcode number.
CURLcode is one of the following:
CURLE_OK (0)
All fine. Proceed as usual.
CURLE_UNSUPPORTED_PROTOCOL (1)
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 did not use, it can be a misspelled protocol string or
just a protocol libcurl has no code for.
CURLE_FAILED_INIT (2)
Early initialization code failed. This is likely to be an inter-
nal error or problem, or a resource problem where something fun-
damental could not get done at init time.
CURLE_URL_MALFORMAT (3)
The URL was not properly formatted.
CURLE_NOT_BUILT_IN (4)
A requested feature, protocol or option was not found built-in
in this libcurl due to a build-time decision. This means that a
feature or option was not enabled or explicitly disabled when
libcurl was built and in order to get it to function you have to
get a rebuilt libcurl.
CURLE_COULDNT_RESOLVE_PROXY (5)
Couldn't resolve proxy. The given proxy host could not be re-
solved.
CURLE_COULDNT_RESOLVE_HOST (6)
Couldn't resolve host. The given remote host was not resolved.
CURLE_COULDNT_CONNECT (7)
Failed to connect() to host or proxy.
CURLE_WEIRD_SERVER_REPLY (8)
The server sent data libcurl could not parse. This error code
was known as as CURLE_FTP_WEIRD_SERVER_REPLY before 7.51.0.
CURLE_REMOTE_ACCESS_DENIED (9)
We were denied access to the resource given in the URL. For FTP,
this occurs while trying to change to the remote directory.
CURLE_FTP_ACCEPT_FAILED (10)
While waiting for the server to connect back when an active FTP
session is used, an error code was sent over the control connec-
tion or similar.
CURLE_FTP_WEIRD_PASS_REPLY (11)
After having sent the FTP password to the server, libcurl ex-
pects a proper reply. This error code indicates that an unex-
pected code was returned.
CURLE_FTP_ACCEPT_TIMEOUT (12)
During an active FTP session while waiting for the server to
connect, the CURLOPT_ACCEPTTIMEOUT_MS(3) (or the internal de-
fault) timeout expired.
CURLE_FTP_WEIRD_PASV_REPLY (13)
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 (14)
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 (15)
An internal failure to lookup the host used for the new connec-
tion.
CURLE_HTTP2 (16)
A problem was detected in the HTTP2 framing layer. This is some-
what generic and can be one out of several problems, see the er-
ror buffer for details.
CURLE_FTP_COULDNT_SET_TYPE (17)
Received an error when trying to set the transfer mode to binary
or ASCII.
CURLE_PARTIAL_FILE (18)
A file transfer was shorter or larger than expected. This hap-
pens when the server first reports an expected transfer size,
and then delivers data that does not match the previously given
size.
CURLE_FTP_COULDNT_RETR_FILE (19)
This was either a weird reply to a 'RETR' command or a zero byte
transfer complete.
CURLE_QUOTE_ERROR (21)
When sending custom "QUOTE" commands to the remote server, one
of the commands returned an error code that was 400 or higher
(for FTP) or otherwise indicated unsuccessful completion of the
command.
CURLE_HTTP_RETURNED_ERROR (22)
This is returned if CURLOPT_FAILONERROR(3) is set TRUE and the
HTTP server returns an error code that is >= 400.
CURLE_WRITE_ERROR (23)
An error occurred when writing received data to a local file, or
an error was returned to libcurl from a write callback.
CURLE_UPLOAD_FAILED (25)
Failed starting the upload. For FTP, the server typically denied
the STOR command. The error buffer usually contains the server's
explanation for this.
CURLE_READ_ERROR (26)
There was a problem reading a local file or an error returned by
the read callback.
CURLE_OUT_OF_MEMORY (27)
A memory allocation request failed. This is serious badness and
things are severely screwed up if this ever occurs.
CURLE_OPERATION_TIMEDOUT (28)
Operation timeout. The specified time-out period was reached ac-
cording to the conditions.
CURLE_FTP_PORT_FAILED (30)
The FTP PORT command returned error. This mostly happens when
you have not specified a good enough address for libcurl to use.
See CURLOPT_FTPPORT(3).
CURLE_FTP_COULDNT_USE_REST (31)
The FTP REST command returned error. This should never happen if
the server is sane.
CURLE_RANGE_ERROR (33)
The server does not support or accept range requests.
CURLE_HTTP_POST_ERROR (34)
This is an odd error that mainly occurs due to internal confu-
sion.
CURLE_SSL_CONNECT_ERROR (35)
A problem occurred somewhere in the SSL/TLS handshake. You re-
ally want the error buffer and read the message there as it pin-
points the problem slightly more. Could be certificates (file
formats, paths, permissions), passwords, and others.
CURLE_BAD_DOWNLOAD_RESUME (36)
The download could not be resumed because the specified offset
was out of the file boundary.
CURLE_FILE_COULDNT_READ_FILE (37)
A file given with FILE:// could not be opened. Most likely be-
cause the file path does not identify an existing file. Did you
check file permissions?
CURLE_LDAP_CANNOT_BIND (38)
LDAP cannot bind. LDAP bind operation failed.
CURLE_LDAP_SEARCH_FAILED (39)
LDAP search failed.
CURLE_FUNCTION_NOT_FOUND (41)
Function not found. A required zlib function was not found.
CURLE_ABORTED_BY_CALLBACK (42)
Aborted by callback. A callback returned "abort" to libcurl.
CURLE_BAD_FUNCTION_ARGUMENT (43)
A function was called with a bad parameter.
CURLE_INTERFACE_FAILED (45)
Interface error. A specified outgoing interface could not be
used. Set which interface to use for outgoing connections'
source IP address with CURLOPT_INTERFACE(3).
CURLE_TOO_MANY_REDIRECTS (47)
Too many redirects. When following redirects, libcurl hit the
maximum amount. Set your limit with CURLOPT_MAXREDIRS(3).
CURLE_UNKNOWN_OPTION (48)
An option passed to libcurl is not recognized/known. Refer to
the appropriate documentation. This is most likely a problem in
the program that uses libcurl. The error buffer might contain
more specific information about which exact option it concerns.
CURLE_SETOPT_OPTION_SYNTAX (49)
An option passed in to a setopt was wrongly formatted. See error
message for details about what option.
CURLE_GOT_NOTHING (52)
Nothing was returned from the server, and under the circum-
stances, getting nothing is considered an error.
CURLE_SSL_ENGINE_NOTFOUND (53)
The specified crypto engine was not found.
CURLE_SSL_ENGINE_SETFAILED (54)
Failed setting the selected SSL crypto engine as default.
CURLE_SEND_ERROR (55)
Failed sending network data.
CURLE_RECV_ERROR (56)
Failure with receiving network data.
CURLE_SSL_CERTPROBLEM (58)
problem with the local client certificate.
CURLE_SSL_CIPHER (59)
Couldn't use specified cipher.
CURLE_PEER_FAILED_VERIFICATION (60)
The remote server's SSL certificate or SSH md5 fingerprint was
deemed not OK. This error code has been unified with
CURLE_SSL_CACERT since 7.62.0. Its previous value was 51.
CURLE_BAD_CONTENT_ENCODING (61)
Unrecognized transfer encoding.
CURLE_LDAP_INVALID_URL (62)
Invalid LDAP URL.
CURLE_FILESIZE_EXCEEDED (63)
Maximum file size exceeded.
CURLE_USE_SSL_FAILED (64)
Requested FTP SSL level failed.
CURLE_SEND_FAIL_REWIND (65)
When doing a send operation curl had to rewind the data to re-
transmit, but the rewinding operation failed.
CURLE_SSL_ENGINE_INITFAILED (66)
Initiating the SSL Engine failed.
CURLE_LOGIN_DENIED (67)
The remote server denied curl to login (Added in 7.13.1)
CURLE_TFTP_NOTFOUND (68)
File not found on TFTP server.
CURLE_TFTP_PERM (69)
Permission problem on TFTP server.
CURLE_REMOTE_DISK_FULL (70)
Out of disk space on the server.
CURLE_TFTP_ILLEGAL (71)
Illegal TFTP operation.
CURLE_TFTP_UNKNOWNID (72)
Unknown TFTP transfer ID.
CURLE_REMOTE_FILE_EXISTS (73)
File already exists and will not be overwritten.
CURLE_TFTP_NOSUCHUSER (74)
This error should never be returned by a properly functioning
TFTP server.
CURLE_CONV_FAILED (75)
Character conversion failed.
CURLE_CONV_REQD (76)
Caller must register conversion callbacks.
CURLE_SSL_CACERT_BADFILE (77)
Problem with reading the SSL CA cert (path? access rights?)
CURLE_REMOTE_FILE_NOT_FOUND (78)
The resource referenced in the URL does not exist.
CURLE_SSH (79)
An unspecified error occurred during the SSH session.
CURLE_SSL_SHUTDOWN_FAILED (80)
Failed to shut down the SSL connection.
CURLE_AGAIN (81)
Socket is not ready for send/recv wait till it's ready and try
again. This return code is only returned from curl_easy_recv(3)
and curl_easy_send(3) (Added in 7.18.2)
CURLE_SSL_CRL_BADFILE (82)
Failed to load CRL file (Added in 7.19.0)
CURLE_SSL_ISSUER_ERROR (83)
Issuer check failed (Added in 7.19.0)
CURLE_FTP_PRET_FAILED (84)
The FTP server does not understand the PRET command at all or
does not support the given argument. Be careful when using CUR-
LOPT_CUSTOMREQUEST(3), a custom LIST command will be sent with
PRET CMD before PASV as well. (Added in 7.20.0)
CURLE_RTSP_CSEQ_ERROR (85)
Mismatch of RTSP CSeq numbers.
CURLE_RTSP_SESSION_ERROR (86)
Mismatch of RTSP Session Identifiers.
CURLE_FTP_BAD_FILE_LIST (87)
Unable to parse FTP file list (during FTP wildcard downloading).
CURLE_CHUNK_FAILED (88)
Chunk callback reported error.
CURLE_NO_CONNECTION_AVAILABLE (89)
(For internal use only, will never be returned by libcurl) No
connection available, the session will be queued. (added in
7.30.0)
CURLE_SSL_PINNEDPUBKEYNOTMATCH (90)
Failed to match the pinned key specified with CURLOPT_PINNEDPUB-
LICKEY(3).
CURLE_SSL_INVALIDCERTSTATUS (91)
Status returned failure when asked with CURLOPT_SSL_VERIFYSTA-
TUS(3).
CURLE_HTTP2_STREAM (92)
Stream error in the HTTP/2 framing layer.
CURLE_RECURSIVE_API_CALL (93)
An API function was called from inside a callback.
CURLE_AUTH_ERROR (94)
An authentication function returned an error.
CURLE_HTTP3 (95)
A problem was detected in the HTTP/3 layer. This is somewhat
generic and can be one out of several problems, see the error
buffer for details.
CURLE_QUIC_CONNECT_ERROR (96)
QUIC connection error. This error may be caused by an SSL li-
brary error. QUIC is the protocol used for HTTP/3 transfers.
CURLE_SSL_CLIENTCERT (98)
SSL Client Certificate required.
CURLE_OBSOLETE*
These error codes will never be returned. They were used in an
old libcurl version and are currently unused.
CURLMcode
This is the generic return code used by functions in the libcurl multi
interface. Also consider curl_multi_strerror(3).
CURLM_CALL_MULTI_PERFORM (-1)
This is not really an error. It means you should call
curl_multi_perform(3) again without doing select() or similar in
between. Before version 7.20.0 (released on February 9 2010)
this could be returned by curl_multi_perform(3), but in later
versions this return code is never used.
CURLM_CALL_MULTI_SOCKET (-1)
An alias for CURLM_CALL_MULTI_PERFORM. Never returned by modern
libcurl versions.
CURLM_OK (0)
Things are fine.
CURLM_BAD_HANDLE (1)
The passed-in handle is not a valid CURLM handle.
CURLM_BAD_EASY_HANDLE (2)
An easy handle was not good/valid. It could mean that it is not
an easy handle at all, or possibly that the handle already is in
use by this or another multi handle.
CURLM_OUT_OF_MEMORY (3)
You are doomed.
CURLM_INTERNAL_ERROR (4)
This can only be returned if libcurl bugs. Please report it to
us!
CURLM_BAD_SOCKET (5)
The passed-in socket is not a valid one that libcurl already
knows about. (Added in 7.15.4)
CURLM_UNKNOWN_OPTION (6)
curl_multi_setopt() with unsupported option (Added in 7.15.4)
CURLM_ADDED_ALREADY (7)
An easy handle already added to a multi handle was attempted to
get added a second time. (Added in 7.32.1)
CURLM_RECURSIVE_API_CALL (8)
An API function was called from inside a callback.
CURLM_WAKEUP_FAILURE (9)
Wakeup is unavailable or failed.
CURLM_BAD_FUNCTION_ARGUMENT (10)
A function was called with a bad parameter.
CURLM_ABORTED_BY_CALLBACK (11)
A multi handle callback returned error.
CURLSHcode
The "share" interface will return a CURLSHcode to indicate when an er-
ror has occurred. Also consider curl_share_strerror(3).
CURLSHE_OK (0)
All fine. Proceed as usual.
CURLSHE_BAD_OPTION (1)
An invalid option was passed to the function.
CURLSHE_IN_USE (2)
The share object is currently in use.
CURLSHE_INVALID (3)
An invalid share object was passed to the function.
CURLSHE_NOMEM (4)
Not enough memory was available. (Added in 7.12.0)
CURLSHE_NOT_BUILT_IN (5)
The requested sharing could not be done because the library you
use do not have that particular feature enabled. (Added in
7.23.0)
CURLUcode
The URL interface will return a CURLUcode to indicate when an error has
occurred. Also consider curl_url_strerror(3).
CURLUE_BAD_HANDLE (1)
An invalid CURLU pointer was passed as argument.
CURLUE_BAD_PARTPOINTER (2)
An invalid 'part' argument was passed as argument.
CURLUE_MALFORMED_INPUT (3)
A malformed input was passed to a URL API function.
CURLUE_BAD_PORT_NUMBER (4)
The port number was not a decimal number between 0 and 65535.
CURLUE_UNSUPPORTED_SCHEME (5)
This libcurl build does not support the given URL scheme.
CURLUE_URLDECODE (6)
URL decode error, most likely because of rubbish in the input.
CURLUE_OUT_OF_MEMORY (7)
A memory function failed.
CURLUE_USER_NOT_ALLOWED (8)
Credentials was passed in the URL when prohibited.
CURLUE_UNKNOWN_PART (9)
An unknown part ID was passed to a URL API function.
CURLUE_NO_SCHEME (10)
There is no scheme part in the URL.
CURLUE_NO_USER (11)
There is no user part in the URL.
CURLUE_NO_PASSWORD (12)
There is no password part in the URL.
CURLUE_NO_OPTIONS (13)
There is no options part in the URL.
CURLUE_NO_HOST (14)
There is no host part in the URL.
CURLUE_NO_PORT (15)
There is no port part in the URL.
CURLUE_NO_QUERY (16)
There is no query part in the URL.
CURLUE_NO_FRAGMENT (17)
There is no fragment part in the URL.
CURLUE_NO_ZONEID (18)
There is no zoneid set in the URL.
CURLUE_BAD_FILE_URL (19)
The file:// URL is invalid.
CURLUE_BAD_FRAGMENT (20)
The fragment part of the URL contained bad or invalid charac-
ters.
CURLUE_BAD_HOSTNAME (21)
The hostname contained bad or invalid characters.
CURLUE_BAD_IPV6 (22)
The IPv6 address hostname contained bad or invalid characters.
CURLUE_BAD_LOGIN (23)
The login part of the URL contained bad or invalid characters.
CURLUE_BAD_PASSWORD (24)
The password part of the URL contained bad or invalid charac-
ters.
CURLUE_BAD_PATH (25)
The path part of the URL contained bad or invalid characters.
CURLUE_BAD_QUERY (26)
The query part of the URL contained bad or invalid characters.
CURLUE_BAD_SCHEME (27)
The scheme part of the URL contained bad or invalid characters.
CURLUE_BAD_SLASHES (28)
The URL contained an invalid number of slashes.
CURLUE_BAD_USER (29)
The user part of the URL contained bad or invalid characters.
SEE ALSO
curl_easy_strerror(3), curl_multi_strerror(3), curl_share_strerror(3),
curl_url_strerror(3), CURLOPT_ERRORBUFFER(3), CURLOPT_VERBOSE(3), CUR-
LOPT_DEBUGFUNCTION(3)
libcurl 7.81.0 December 08, 2021 libcurl-errors(3)
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