curl_version_info (3)

#include <curl/curl.h>

curl_version_info_data *curl_version_info( CURLversion type);

Returns a pointer to a filled in static struct with information about various features in the running version of libcurl. type should be set to the version of this functionality by the time you write your program. This way, libcurl will always return a proper struct that your program understands, while programs in the future might get a different struct. CURLVERSION_NOW will be the most recent one for the library you have installed:

        data = curl_version_info(CURLVERSION_NOW);

Applications should use this information to judge if things are possible to do or not, instead of using compile-time checks, as dynamic/DLL libraries can be changed independent of applications.

The curl_version_info_data struct looks like this

typedef struct {
  CURLversion age;          /* see description below */

  /* when 'age' is 0 or higher, the members below also exist: */
  const char *version;      /* human readable string */
  unsigned int version_num; /* numeric representation */
  const char *host;         /* human readable string */
  int features;             /* bitmask, see below */
  char *ssl_version;        /* human readable string */
  long ssl_version_num;     /* not used, always zero */
  const char *libz_version; /* human readable string */
  const char **protocols;   /* list of protocols */

  /* when 'age' is 1 or higher, the members below also exist: */
  const char *ares;         /* human readable string */
  int ares_num;             /* number */

  /* when 'age' is 2 or higher, the member below also exists: */
  const char *libidn;       /* human readable string */

  /* when 'age' is 3 or higher (7.16.1 or later), the members below also
     exist  */
  int iconv_ver_num;       /* '_libiconv_version' if iconv support enabled */

  const char *libssh_version; /* human readable string */

} curl_version_info_data;

age describes what the age of this struct is. The number depends on how new the libcurl you're using is. You are however guaranteed to get a struct that you have a matching struct for in the header, as you tell libcurl your "age" with the input argument.

version is just an ascii string for the libcurl version.

version_num is a 24 bit number created like this: <8 bits major number> | <8 bits minor number> | <8 bits patch number>. Version 7.9.8 is therefore returned as 0x070908.

host is an ascii string showing what host information that this libcurl was built for. As discovered by a configure script or set by the build environment.

features can have none, one or more bits set, and the currently defined bits are:

CURL_VERSION_IPV6

supports IPv6

CURL_VERSION_KERBEROS4

supports kerberos4 (when using FTP)

CURL_VERSION_SSL

supports SSL (HTTPS/FTPS) (Added in 7.10)

CURL_VERSION_LIBZ

supports HTTP deflate using libz (Added in 7.10)

CURL_VERSION_NTLM

supports HTTP NTLM (added in 7.10.6)

CURL_VERSION_GSSNEGOTIATE

supports HTTP GSS-Negotiate (added in 7.10.6)

CURL_VERSION_DEBUG

libcurl was built with debug capabilities (added in 7.10.6)

CURL_VERSION_CURLDEBUG

libcurl was built with memory tracking debug capabilities. This is mainly of interest for libcurl hackers. (added in 7.19.6)

CURL_VERSION_ASYNCHDNS

libcurl was built with support for asynchronous name lookups, which allows more exact timeouts (even on Windows) and less blocking when using the multi interface. (added in 7.10.7)

CURL_VERSION_SPNEGO

libcurl was built with support for SPNEGO authentication (Simple and Protected GSS-API Negotiation Mechanism, defined in RFC 2478.) (added in 7.10.8)

CURL_VERSION_LARGEFILE

libcurl was built with support for large files. (Added in 7.11.1)

CURL_VERSION_IDN

libcurl was built with support for IDNA, domain names with international letters. (Added in 7.12.0)

CURL_VERSION_SSPI

libcurl was built with support for SSPI. This is only available on Windows and makes libcurl use Windows-provided functions for NTLM, SPNEGO and SASL DIGEST-MD5 authentication. It also allows libcurl to use the current user credentials without the app having to pass them on. (Added in 7.13.2)

CURL_VERSION_GSSAPI

libcurl was built with support for GSS-API. This makes libcurl use provided functions for Kerberos and SPNEGO authentication. It also allows libcurl to use the current user credentials without the app having to pass them on. (Added in 7.38.0)

CURL_VERSION_CONV

libcurl was built with support for character conversions, as provided by the CURLOPT_CONV_* callbacks. (Added in 7.15.4)

CURL_VERSION_TLSAUTH_SRP

libcurl was built with support for TLS-SRP. (Added in 7.21.4)

CURL_VERSION_NTLM_WB

libcurl was built with support for NTLM delegation to a winbind helper. (Added in 7.22.0)

CURL_VERSION_HTTP2

libcurl was built with support for HTTP2. (Added in 7.33.0)

ssl_version is an ASCII string for the OpenSSL version used. If libcurl has no SSL support, this is NULL.

ssl_version_num is always 0.

libz_version is an ASCII string (there is no numerical version). If libcurl has no libz support, this is NULL.

protocols is a pointer to an array of char * pointers, containing the names protocols that libcurl supports (using lowercase letters). The protocol names are the same as would be used in URLs. The array is terminated by a NULL entry.

A pointer to a curl_version_info_data struct.

curl_version(3)