+static int close_perhaps(int *fd) {
+ if (!*fd) return 0;
+ int r= close(*fd);
+ *fd=0;
+ return r;
+}
+static void xclose(int fd, const char *what, const char *what2) {
+ int r= close(fd);
+ if (r) sysdie("close %s%s",what,what2?what2:"");
+}
+static void xclose_perhaps(int *fd, const char *what, const char *what2) {
+ if (!*fd) return;
+ xclose(*fd,what,what2);
+ *fd=0;
+}