Index: b/popen.c
===================================================================
--- b/popen.c
+++ b/popen.c
@@ -145,7 +145,6 @@
 	}
 	THREAD_UNLOCK();
 
-	/* Parent; assume fdopen can't fail. */
 	if (*type == 'r') {
 		iop = fdopen(pdes[0], type);
 		(void)_close(pdes[1]);
@@ -154,6 +153,13 @@
 		(void)_close(pdes[0]);
 	}
 
+	/* Parent: adding check for fdopen failure. */
+	if (iop == NULL) {
+		(void)_close(pdes[(*type == 'r') ? 0 : 1]); /* close used pipe-end */
+		free(cur);
+		return (NULL);
+	}
+
 	/* Link into list of file descriptors. */
 	cur->fp = iop;
 	cur->pid = pid;