text: #include <errno.h>
  #include <string.h>
  
  #include <netlink/genl/genl.h>
  #include <netlink/msg.h>
  #include <netlink/attr.h>
  
  #include "nl80211.h"
  #include "iw.h"
  
  static int set_power_save(struct nl80211_state *state,
  			  struct nl_msg *msg,
  			  int argc, char **argv,
  			  enum id_input id)
  {
  	enum nl80211_ps_state ps_state;
  
  	if (argc != 1) {
  		printf("Invalid parameters!\n");
  		return 2;
  	}
  
  	if (strcmp(argv[0], "on") == 0)
  		ps_state = NL80211_PS_ENABLED;
  	else if (strcmp(argv[0], "off") == 0)
  		ps_state = NL80211_PS_DISABLED;
  	else {
  		printf("Invalid parameter: %s\n", argv[0]);
  		return 2;
  	}
  
  	NLA_PUT_U32(msg, NL80211_ATTR_PS_STATE, ps_state);
  
  	return 0;
  
   nla_put_failure:
  	return -ENOBUFS;
  }
  
  COMMAND(set, power_save, "<on|off>",
  	NL80211_CMD_SET_POWER_SAVE, 0, CIB_NETDEV, set_power_save,
  	"Set power save state to on or off.");
  
  static int print_power_save_handler(struct nl_msg *msg, void *arg)
  {
  	struct nlattr *attrs[NL80211_ATTR_MAX + 1];
  	struct genlmsghdr *gnlh = nlmsg_data(nlmsg_hdr(msg));
  	const char *s;
  
  	nla_parse(attrs, NL80211_ATTR_MAX, genlmsg_attrdata(gnlh, 0),
  		  genlmsg_attrlen(gnlh, 0), NULL);
  
  	if (!attrs[NL80211_ATTR_PS_STATE])
  		return NL_SKIP;
  
  	switch (nla_get_u32(attrs[NL80211_ATTR_PS_STATE])) {
  	case NL80211_PS_ENABLED:
  		s = "on";
  		break;
  	case NL80211_PS_DISABLED:
  	default:
  		s = "off";
  		break;
  	}
  
  	printf("Power save: %s\n", s);
  
  	return NL_SKIP;
  }
  
  static int get_power_save(struct nl80211_state *state,
  			  struct nl_msg *msg,
  			  int argc, char **argv,
  			  enum id_input id)
  {
  	register_handler(print_power_save_handler, NULL);
  	return 0;
  }
  
  COMMAND(get, power_save, "<param>",
  	NL80211_CMD_GET_POWER_SAVE, 0, CIB_NETDEV, get_power_save,
  	"Retrieve power save state.");
  