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Introduction

libdeltacloud is a library for accessing the deltacloud API through a convenient C library.

API and ABI stability

As of version 0.9, libdeltacloud is mostly API, but not ABI, stable. The difference between the two is subtle but important. A library that is ABI (Application Binary Interface) stable means that programs that use the library will not need to be modified nor re-compiled when a new version of the library comes out. A library that is API (Application Programming Interface) stable means that programs that use the library will not need to be modified, but may need to be re-compiled when a new version of the library comes out. That is because the sizes of structures in the library might change, and a mis-match between what the library thinks the size of a structure is and what the program thinks the size of a structure is is a recipe for disaster.

Due to the magic of libtool versioning, programs built against an older version of libdeltacloud will refuse to run against a newer version of libdeltacloud if the size of the structures has changed. If this happens, then the program must be recompiled against the newer libdeltacloud.

Examples

Connect to deltacloud

 #include <stdio.h>
 #include <stdlib.h>
 #include <libdeltacloud/libdeltacloud.h>

 int main()
 {
   struct deltacloud_api api;

   if (deltacloud_initialize(&api, "http://localhost:3001/api", "mockuser",
                             "mockpassword") < 0) {
       fprintf(stderr, "Failed to initialize libdeltacloud: %s\n",
               deltacloud_get_last_error_string());
       return 1;
   }

   deltacloud_free(&api);
   return 0;
 }

List all running instances

 #include <stdio.h>
 #include <stdlib.h>
 #include <libdeltacloud/libdeltacloud.h>

 int main()
 {
   struct deltacloud_api api;
   struct deltacloud_instances *instances = NULL;
   int ret = 2;

   if (deltacloud_initialize(&api, "http://localhost:3001/api", "mockuser",
                             "mockpassword") < 0) {
       fprintf(stderr, "Failed to initialize libdeltacloud: %s\n",
               deltacloud_get_last_error_string());
       return 1;
   }

   if (deltacloud_get_instances(&api, &instances) < 0) {
       fprintf(stderr, "Failed to get deltacloud instances: %s\n",
               deltacloud_get_last_error_string());
       goto cleanup;
   }

   deltacloud_free_instance_list(&instances);

   ret = 0;

  cleanup:
   deltacloud_free(&api);
   return ret;
 }