curl_easy_setopt.3

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directory, instead of doing a full directory listing that would include file
sizes, dates etc.

This causes an FTP NLST command to be sent.  Beware that some FTP servers list
only files in their response to NLST; they might not include subdirectories
and symbolic links.
.TP
.B CURLOPT_FTPAPPEND
A non-zero parameter tells the library to append to the remote file instead of
overwrite it. This is only useful when uploading to a ftp site.
.TP
.B CURLOPT_FTP_USE_EPRT
Pass a long. If the value is non-zero, it tells curl to use the EPRT (and
LPRT) command when doing active FTP downloads (which is enabled by
CURLOPT_FTPPORT). Using EPRT means that it will first attempt to use EPRT and
then LPRT before using PORT, but if you pass FALSE (zero) to this option, it
will not try using EPRT or LPRT, only plain PORT. (Added in 7.10.5)
.TP
.B CURLOPT_FTP_USE_EPSV
Pass a long. If the value is non-zero, it tells curl to use the EPSV command
when doing passive FTP downloads (which it always does by default). Using EPSV
means that it will first attempt to use EPSV before using PASV, but if you
pass FALSE (zero) to this option, it will not try using EPSV, only plain PASV.
.TP
.B CURLOPT_FTP_CREATE_MISSING_DIRS
Pass a long. If the value is non-zero, curl will attempt to create any remote
directory that it fails to CWD into. CWD is the command that changes working
directory. (Added in 7.10.7)
.TP
.B CURLOPT_FTP_RESPONSE_TIMEOUT
Pass a long.  Causes curl to set a timeout period (in seconds) on the amount
of time that the server is allowed to take in order to generate a response
message for a command before the session is considered hung.  Note that while 
curl is waiting for a response, this value overrides CURLOPT_TIMEOUT. It is 
recommended that if used in conjunction with CURLOPT_TIMEOUT, you set 
CURLOPT_FTP_RESPONSE_TIMEOUT to a value smaller than CURLOPT_TIMEOUT.
(Added in 7.10.8)
.PP
.SH PROTOCOL OPTIONS
.TP 0.4i
.B CURLOPT_TRANSFERTEXT
A non-zero parameter tells the library to use ASCII mode for ftp transfers,
instead of the default binary transfer. For LDAP transfers it gets the data in
plain text instead of HTML and for win32 systems it does not set the stdout to
binary mode. This option can be usable when transferring text data between
systems with different views on certain characters, such as newlines or
similar.
.TP
.B CURLOPT_CRLF
Convert Unix newlines to CRLF newlines on transfers.
.TP
.B CURLOPT_RANGE
Pass a char * as parameter, which should contain the specified range you
want. It should be in the format "X-Y", where X or Y may be left out. HTTP
transfers also support several intervals, separated with commas as in
\fI"X-Y,N-M"\fP. Using this kind of multiple intervals will cause the HTTP
server to send the response document in pieces (using standard MIME separation
techniques).
.TP
.B CURLOPT_RESUME_FROM
Pass a long as parameter. It contains the offset in number of bytes that you
want the transfer to start from.
.TP
.B CURLOPT_CUSTOMREQUEST
Pass a pointer to a zero terminated string as parameter. It will be user
instead of GET or HEAD when doing a HTTP request, or instead of LIST or NLST
when doing an ftp directory listing. This is useful for doing DELETE or other
more or less obscure HTTP requests. Don't do this at will, make sure your
server supports the command first.

NOTE: many people have wrongly used this option to replace the entire request
with their own, including multiple headers and POST contents. While that might
work in many cases, it will cause libcurl to send invalid requests and it
could possibly confuse the remote server badly. Use \fICURLOPT_POST\fP and
\fICURLOPT_POSTFIELDS\fP to set POST data. Use \fICURLOPT_HTTPHEADER\fP to
replace or extend the set of headers sent by libcurl. Use
\fICURLOPT_HTTP_VERSION\fP to change HTTP version.
.TP
.B CURLOPT_FILETIME
Pass a long. If it is a non-zero value, libcurl will attempt to get the
modification date of the remote document in this operation. This requires that
the remote server sends the time or replies to a time querying command. The
\fIcurl_easy_getinfo(3)\fP function with the \fICURLINFO_FILETIME\fP argument
can be used after a transfer to extract the received time (if any).
.TP
.B CURLOPT_NOBODY
A non-zero parameter tells the library to not include the body-part in the
output. This is only relevant for protocols that have separate header and body
parts. On HTTP(S) servers, this will make libcurl do a HEAD request.
.TP
.B CURLOPT_INFILESIZE
When uploading a file to a remote site, this option should be used to tell
libcurl what the expected size of the infile is.
.TP
.B CURLOPT_UPLOAD
A non-zero parameter tells the library to prepare for an upload. The
CURLOPT_READDATA and CURLOPT_INFILESIZE are also interesting for uploads.
.TP
.B CURLOPT_MAXFILESIZE
Pass a long as parameter. This allows you to specify the maximum size (in
bytes) of a file to download. If the file requested is larger than this value,
the transfer will not start and CURLE_FILESIZE_EXCEEDED will be returned.

NOTE: The file size is not always known prior to download, and for such files
this option has no effect even if the file transfer ends up being larger than
this given limit. This concerns both FTP and HTTP transfers.
.PP
.SH CONNECTION OPTIONS
.TP 0.4i
.B CURLOPT_TIMEOUT
Pass a long as parameter containing the maximum time in seconds that you allow
the libcurl transfer operation to take. Normally, name lookups can take a
considerable time and limiting operations to less than a few minutes risk
aborting perfectly normal operations. This option will cause curl to use the
SIGALRM to enable time-outing system calls.

\fBNOTE:\fP this is not recommended to use in unix multi-threaded programs, as
it uses signals unless CURLOPT_NOSIGNAL (see above) is set.
.TP
.B CURLOPT_LOW_SPEED_LIMIT
Pass a long as parameter. It contains the transfer speed in bytes per second
that the transfer should be below during CURLOPT_LOW_SPEED_TIME seconds for
the library to consider it too slow and abort.
.TP
.B CURLOPT_LOW_SPEED_TIME
Pass a long as parameter. It contains the time in seconds that the transfer
should be below the CURLOPT_LOW_SPEED_LIMIT for the library to consider it too
slow and abort.
.TP
.B CURLOPT_MAXCONNECTS
Pass a long. The set number will be the persistent connection cache size. The
set amount will be the maximum amount of simultaneously open connections that
libcurl may cache. Default is 5, and there isn't much point in changing this
value unless you are perfectly aware of how this work and changes libcurl's
behaviour. This concerns connection using any of the protocols that support
persistent connections.

When reaching the maximum limit, curl uses the \fICURLOPT_CLOSEPOLICY\fP to
figure out which of the existing connections to close to prevent the number of
open connections to increase.

\fBNOTE:\fP if you already have performed transfers with this curl handle,
setting a smaller MAXCONNECTS than before may cause open connections to get
closed unnecessarily.
.TP
.B CURLOPT_CLOSEPOLICY
Pass a long. This option sets what policy libcurl should use when the
connection cache is filled and one of the open connections has to be closed to
make room for a new connection. This must be one of the CURLCLOSEPOLICY_*
defines. Use \fICURLCLOSEPOLICY_LEAST_RECENTLY_USED\fP to make libcurl close
the connection that was least recently used, that connection is also least
likely to be capable of re-use. Use \fICURLCLOSEPOLICY_OLDEST\fP to make
libcurl close the oldest connection, the one that was created first among the
ones in the connection cache. The other close policies are not support
yet.
.TP
.B CURLOPT_FRESH_CONNECT
Pass a long. Set to non-zero to make the next transfer use a new (fresh)
connection by force. If the connection cache is full before this connection,
one of the existing connections will be closed as according to the selected or
default policy. This option should be used with caution and only if you
understand what it does. Set this to 0 to have libcurl attempt re-using an
existing connection (default behavior).
.TP
.B CURLOPT_FORBID_REUSE
Pass a long. Set to non-zero to make the next transfer explicitly close the
connection when done. Normally, libcurl keep all connections alive when done
with one transfer in case there comes a succeeding one that can re-use them.
This option should be used with caution and only if you understand what it
does. Set to 0 to have libcurl keep the connection open for possibly later
re-use (default behavior).
.TP
.B CURLOPT_CONNECTTIMEOUT
Pass a long. It should contain the maximum time in seconds that you allow the
connection to the server to take.  This only limits the connection phase, once
it has connected, this option is of no more use. Set to zero to disable
connection timeout (it will then only timeout on the system's internal
timeouts). See also the \fICURLOPT_TIMEOUT\fP option.

\fBNOTE:\fP this is not recommended to use in unix multi-threaded programs, as
it uses signals unless CURLOPT_NOSIGNAL (see above) is set.
.PP
.SH SSL and SECURITY OPTIONS
.TP 0.4i
.B CURLOPT_SSLCERT
Pass a pointer to a zero terminated string as parameter. The string should be
the file name of your certificate. The default format is "PEM" and can be
changed with \fICURLOPT_SSLCERTTYPE\fP.
.TP
.B CURLOPT_SSLCERTTYPE
Pass a pointer to a zero terminated string as parameter. The string should be
the format of your certificate. Supported formats are "PEM" and "DER".  (Added
in 7.9.3)
.TP
.B CURLOPT_SSLCERTPASSWD
Pass a pointer to a zero terminated string as parameter. It will be used as
the password required to use the CURLOPT_SSLCERT certificate. If the password
is not supplied, you will be prompted for it. \fICURLOPT_PASSWDFUNCTION\fP can
be used to set your own prompt function.

\fBNOTE:\fPThis option is replaced by \fICURLOPT_SSLKEYPASSWD\fP and only
cept for backward compatibility. You never needed a pass phrase to load
a certificate but you need one to load your private key.
.TP
.B CURLOPT_SSLKEY
Pass a pointer to a zero terminated string as parameter. The string should be
the file name of your private key. The default format is "PEM" and can be
changed with \fICURLOPT_SSLKEYTYPE\fP.
.TP
.B CURLOPT_SSLKEYTYPE
Pass a pointer to a zero terminated string as parameter. The string should be
the format of your private key. Supported formats are "PEM", "DER" and "ENG".

\fBNOTE:\fPThe format "ENG" enables you to load the private key from a crypto
engine. in this case \fICURLOPT_SSLKEY\fP is used as an identifier passed to
the engine. You have to set the crypto engine with \fICURLOPT_SSL_ENGINE\fP.
.TP
.B CURLOPT_SSLKEYPASSWD
Pass a pointer to a zero terminated string as parameter. It will be used as
the password required to use the \fICURLOPT_SSLKEY\fP private key. If the
password is not supplied, you will be prompted for
it. \fICURLOPT_PASSWDFUNCTION\fP can be used to set your own prompt function.
.TP
.B CURLOPT_SSL_ENGINE
Pass a pointer to a zero terminated string as parameter. It will be used as
the identifier for the crypto engine you want to use for your private
key.

\fBNOTE:\fPIf the crypto device cannot be loaded,
\fICURLE_SSL_ENGINE_NOTFOUND\fP is returned.
.TP
.B CURLOPT_SSL_ENGINEDEFAULT
Sets the actual crypto engine as the default for (asymetric) crypto
operations.

\fBNOTE:\fPIf the crypto device cannot be set,
\fICURLE_SSL_ENGINE_SETFAILED\fP is returned.
.TP
.B CURLOPT_SSLVERSION
Pass a long as parameter. Set what version of SSL to attempt to use, 2 or
3. By default, the SSL library will try to solve this by itself although some
servers make this difficult why you at times may have to use this option.
.TP
.B CURLOPT_SSL_VERIFYPEER
Pass a long that is set to a zero value to stop curl from verifying the peer's
certificate (7.10 starting setting this option to TRUE by default).  Alternate
certificates to verify against can be specified with the CURLOPT_CAINFO option
or a certificate directory can be specified with the CURLOPT_CAPATH option
(Added in 7.9.8).  As of 7.10, curl installs a default bundle.
CURLOPT_SSL_VERIFYHOST may also need to be set to 1 or 0 if
CURLOPT_SSL_VERIFYPEER is disabled (it defaults to 2).
.TP
.B CURLOPT_CAINFO
Pass a char * to a zero terminated string naming a file holding one or more
certificates to verify the peer with. This only makes sense when used in
combination with the CURLOPT_SSL_VERIFYPEER option.
.TP
.B CURLOPT_CAPATH
Pass a char * to a zero terminated string naming a directory holding multiple
CA certificates to verify the peer with. The certificate directory must be
prepared using the openssl c_rehash utility. This only makes sense when used
in combination with the CURLOPT_SSL_VERIFYPEER option. The CAPATH function
apparently does not work in Windows due to some limitation in openssl. (Added
in 7.9.8)
.TP
.B CURLOPT_RANDOM_FILE
Pass a char * to a zero terminated file name. The file will be used to read
from to seed the random engine for SSL. The more random the specified file is,
the more secure the SSL connection will become.
.TP
.B CURLOPT_EGDSOCKET
Pass a char * to the zero terminated path name to the Entropy Gathering Daemon
socket. It will be used to seed the random engine for SSL.
.TP
.B CURLOPT_SSL_VERIFYHOST
Pass a long. Set if we should verify the Common name from the peer certificate
in the SSL handshake, set 1 to check existence, 2 to ensure that it matches
the provided hostname. This is by default set to 2. (default changed in 7.10)
.TP
.B CURLOPT_SSL_CIPHER_LIST
Pass a char *, pointing to a zero terminated string holding the list of
ciphers to use for the SSL connection. The list must be syntactly correct, it
consists of one or more cipher strings separated by colons. Commas or spaces
are also acceptable separators but colons are normally used, \!, \- and \+ can
be used as operators. Valid examples of cipher lists include 'RC4-SHA',
\'SHA1+DES\', 'TLSv1' and 'DEFAULT'. The default list is normally set when you
compile OpenSSL.

You'll find more details about cipher lists on this URL:
\fIhttp://www.openssl.org/docs/apps/ciphers.html\fP
.TP
.B CURLOPT_KRB4LEVEL
Pass a char * as parameter. Set the krb4 security level, this also enables
krb4 awareness.  This is a string, 'clear', 'safe', 'confidential' or
\&'private'.  If the string is set but doesn't match one of these, 'private'
will be used. Set the string to NULL to disable kerberos4. The kerberos
support only works for FTP.
.PP
.SH OTHER OPTIONS
.TP 0.4i
.B CURLOPT_PRIVATE
Pass a char * as parameter, pointing to data that should be associated with
the curl handle.  The pointer can be subsequently retrieved using the
CURLINFO_PRIVATE options to curl_easy_getinfo. (Added in 7.10.3)
.PP
.SH RETURN VALUE
CURLE_OK (zero) means that the option was set properly, non-zero means an
error occurred as \fI<curl/curl.h>\fP defines. See the \fIlibcurl-errors.3\fP
man page for the full list with descriptions.
.SH "SEE ALSO"
.BR curl_easy_init "(3), " curl_easy_cleanup "(3), "