How to get and compare libcurl version?

问题:

I am using libcurl setting OAuth 2.0 access token. Since libcurl 7.33 CURLcode curl_easy_setopt(CURL *handle, CURLOPT_XOAUTH2_BEARER, char *token); option was added. Now I need to get the libcurl version and compare it with 7.33. In case where version is 7.33 or higher I will use CURLOPT_XOAUTH2_BEARER otherwise I will do something else. I know I should somehow use curl_version_info_data *curl_version_info( CURLversion type ); but I have no idea, how the data in struct look like and how to compare them to 7.33 version. Can someone help me?

回答1:

If you want to detect version at run-time, you can use curl_version_info() in a style like this:

curl_version_info_data *d = curl_version_info(CURLVERSION_NOW);

/* compare with the 24 bit hex number in 8 bit fields */
if(d->version_num >= 0x072100) {
  /* this is libcurl 7.33.0 or later */
  printf("Succcess\n");
}
else {
  printf("A too old version\n");
}

If you prefer to do the detection build-time, you can use a preprocessor #if expression like this:

#include <curl/curl.h>
#if LIBCURL_VERSION_NUM >= 0x072100
 /* this is 7.33.0 or later */
#else
 /* work-around for older libcurls */
#endif

回答2:

As Daniel said, or even just:

#ifdef CURLOPT_XOAUTH2_BEARER
  /* This version supports this option */
#else
  /* No, it doesn't */
#endif