d_t fd[2], int inherit_idx);

 /* Close the given file descriptor, created with _assuan_pipe or one
   of the socket functions.  */
  int (*close) (assuan_context_t ctx, assuan_fd_t fd);


  ssize_t (*read) (assuan_context_t ctx, assuan_fd_t fd, void *buffer,
		   size_t size);
  ssize_t (*write) (assuan_context_t ctx, assuan_fd_t fd,
		    const void *buffer, size_t size);

  int (*recvmsg) (assuan_context_t ctx, assuan_fd_t fd, assuan_msghdr_t msg,
		  int flags);
  int (*sendmsg) (assuan_context_t ctx, assuan_fd_t fd,
		  const assuan_msghdr_t msg, int flags);

  /* If NAME is NULL, don't exec, just fork.  FD_CHILD_LIST is
     modified to reflect the value of the FD in the peer process (on
     Windows).  */
  int (*spawn) (assuan_context_t ctx, assuan_pid_t *r_pid, const char *name,
		const char **argv,
		assuan_fd_t fd_in, assuan_fd_t fd_out,
		assuan_fd_t *fd_child_list,
		void (*atfork) (void *opaque, int reserved),
		void *atforkvalue, unsigned int flags);

  /* If action is 0, like waitpid.  If action is 1, just release the PID?  */
  assuan_pid_t (*waitpid) (assuan_context_t ctx, assuan_pid_t pid,
                           int action, int *status, int options);
  int (*socketpair) (assuan_context_t ctx, int _namespace, int style,
		     int protocol, assuan_fd_t filedes[2]);
  assuan_fd_t (*socket) (assuan_context_t ctx, int _namespace,
                         int style, int protocol);
  int (*connect) (assuan_context_t ctx, assuan_fd_t sock,
                  struct sockaddr *addr, socklen_t length);
};
typedef struct assuan_system_hooks *assuan_system_hooks_t;