Peter Sylvester's CURLOPT_SSL_CTX_FUNCTION docs

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.TH curl_easy_setopt 3 "7 Jan 2004" "libcurl 7.11.0" "libcurl Manual"

.TH curl_easy_setopt 3 "15 Jan 2004" "libcurl 7.11.0" "libcurl Manual"

.SH NAME

curl_easy_setopt - set options for a curl easy handle

.SH SYNOPSIS

set one option in each function call. A typical application uses many

curl_easy_setopt() calls in the setup phase.

Options set with this function call are valid for all forthcoming transfers

performed using this \fIhandle\fP.  The options are not in any way reset

between transfers, so if you want subsequent transfers with different options,

you must change them between the transfers.

\fBNOTE:\fP strings passed to libcurl as 'char *' arguments, will not be

copied by the library. Instead you should keep them available until libcurl no

longer needs them. Failing to do so will cause very odd behavior or even

crashes. libcurl will need them until you call curl_easy_cleanup() or you set

the same option again to use a different pointer.

\fBNOTE2:\fP options set with this function call are valid for the forthcoming

data transfers that are performed when you invoke \fIcurl_easy_perform\fP.

The options are not in any way reset between transfers, so if you want

subsequent transfers with different options, you must change them between the

transfers.

The \fIhandle\fP is the return code from a \fIcurl_easy_init(3)\fP or

\fIcurl_easy_duphandle(3)\fP call.

.SH BEHAVIOR OPTIONS

Pass a pointer to whatever you want passed in to your

\fICURLOPT_DEBUGFUNCTION\fP in the last void * argument. This pointer is not

used by libcurl, it is only passed to the callback.

.IP CURLOPT_SSL_CTX_FUNCTION

Function pointer that should match the following prototype: \fBCURLcode

sslctxfun(CURL *curl, void *sslctx, void *parm);\fP This function gets called

by libcurl just before the initialization of an SSL connection after having

processed all other SSL related options to give a last chance to an

application to modify the behaviour of openssl's ssl initilaization. The

\fIsslctx\fP parameter is actually a pointer to an openssl \fISSL_CTX\fP. If

an error is returned no attempt to establish a connection is made and the

perform operation will return the error code from this callback function.  Set

the \fIparm\fP argument with the \fICURLOPT_SSL_CTX_DATA\fP option. This

option was introduced in 7.11.0.

\fBNOTE:\fP To use this properly, a non-trivial amount of knowledge of the

openssl libraries is necessary. Using this function allows for example to use

openssl callbacks to add additional validation code for certificates, and even

to change the actual URI of an HTTPS request (example used in the lib509 test

case).  See also the example section for a replacement of the key, certificate

and trust file settings.

.IP CURLOPT_SSL_CTX_DATA

Data pointer to pass to the ssl context callback set by the option

\fICURLOPT_SSL_CTX_FUNCTION\fP, this is the pointer you'll get as third

parameter, otherwise \fBNULL\fP. (Added in 7.11.0)

.SH ERROR OPTIONS

.IP CURLOPT_ERRORBUFFER

Pass a char * to a buffer that the libcurl may store human readable error