Updates files in the index and working tree to match the content of the
tree pointed at by the treeish.
@param repo repository to check out (must be non-bare)
@param treeish a commit, tag or tree which content will be used to update
the working directory (or null to use HEAD)
@param opts specifies checkout options (may be null)
@return 0 on success, non-zero return value from notify_cb, or error
code < 0 (use git_error_last for error details)
Updates files in the index and working tree to match the content of the tree pointed at by the treeish.
@param repo repository to check out (must be non-bare) @param treeish a commit, tag or tree which content will be used to update the working directory (or null to use HEAD) @param opts specifies checkout options (may be null) @return 0 on success, non-zero return value from notify_cb, or error code < 0 (use git_error_last for error details)