curl/docs/libcurl/curl_global_sslset.3
Daniel Stenberg 860443bee4
curl_global_sslset.3: clarify
it is a one time *set*, not necessarily a one time use... it can be
called again if the first call failed or just listed the alternatives.

clarify that the available backends are the ones this build supports

plus add some formatting

Reported-by: Rich Gray
Bug: https://curl.haxx.se/mail/lib-2017-08/0119.html
2017-08-30 09:57:05 +02:00

74 lines
3.3 KiB
Groff

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.TH curl_global_sslset 3 "15 July 2017" "libcurl 7.56" "libcurl Manual"
.SH NAME
curl_global_sslset - Select SSL backend to use with libcurl
.SH SYNOPSIS
.B #include <curl/curl.h>
.sp
.BI "CURLsslset curl_global_sslset(curl_sslbackend " id ", const char *" name
.BI ", curl_ssl_backend ***" avail ");"
.ad
.SH DESCRIPTION
This function configures at runtime which SSL backend to use with
libcurl. This function can only be used to select an SSL backend once, and it
must be called \fBbefore\fP \fIcurl_global_init(3)\fP.
The backend can be identified by the \fIid\fP
(e.g. \fBCURLSSLBACKEND_OPENSSL\fP). The backend can also be specified via the
\fIname\fP parameter (passing -1 as \fIid\fP). If both \fIid\fP and \fIname\fP
are specified, the \fIname\fP will be ignored.
If neither \fIid\fP nor \fPname\fP are specified, the function will fail with
CURLSSLSET_UNKNOWN_BACKEND and set the \fIavail\fP pointer to the
NULL-terminated list of available backends. The available backends are those
that this particular build of libcurl supports.
Upon success, the function returns CURLSSLSET_OK.
If the specified SSL backend is not available, the function returns
CURLSSLSET_UNKNOWN_BACKEND and sets the \fIavail\fP pointer to a
NULL-terminated list of available SSL backends. In this case, you may call the
function again to try to select a different backend.
The SSL backend can be set only once. If it has already been set, a subsequent
attempt to change it will result in a \fBCURLSSLSET_TOO_LATE\fP.
\fBThis function is not thread safe.\fP You must not call it when any other
thread in the program (i.e. a thread sharing the same memory) is running.
This doesn't just mean no other thread that is using libcurl.
.SH AVAILABILITY
This function was added in libcurl 7.56.0. Before this version, there was no
support for choosing SSL backends at runtime.
.SH RETURN VALUE
If this function returns CURLSSLSET_OK, the backend was successfully selected.
If the chosen backend is unknown (or support for the chosed backend has not
been compiled into libcurl), the function returns CURLSSLSET_UNKNOWN_BACKEND.
If the backend had been configured previously, or if \fIcurl_global_init(3)\fP
has already been called, the function returns CURLSSLSET_TOO_LATE.
.SH "SEE ALSO"
.BR curl_global_init "(3), "
.BR libcurl "(3) "