main.c

#include <assert.h>
#include <git2/remote.h>
#include <git2/repository.h>
#include <git2/errors.h>
#include <git2/global.h>
#include <stdio.h>

int main() {
  assert(git_libgit2_init() == 1);

  git_repository *repo;
  assert(git_repository_init(&repo, "index-clone", 0) == 0);

  git_remote *remote;
  assert(git_remote_create_anonymous(&remote, repo, "index/.git") == 0);

  git_fetch_options fetch_opts = GIT_FETCH_OPTIONS_INIT;

  char *strings[] = {"HEAD:refs/remotes/origin/head"};
  git_strarray refspecs;
  refspecs.strings = strings;
  refspecs.count = 1;

  int err = git_remote_fetch(remote, &refspecs, &fetch_opts, NULL);
  printf("err = %d\n", err);
  if (err == 0)
    return 0;
  const git_error *last = git_error_last();
  if (last != NULL) {
    printf("message: %s\n", last->message);
    printf("klass: %d\n", last->klass);
  }

  return 0;
}