diff --git a/libnfc/drivers/pcsc.c b/libnfc/drivers/pcsc.c
index 200a11d..e3a1dd7 100644
--- a/libnfc/drivers/pcsc.c
+++ b/libnfc/drivers/pcsc.c
@@ -34,6 +34,7 @@
 #include <stdlib.h>
 #include <stddef.h>
 #include <string.h>
+#include <unistd.h>
 
 #include <nfc/nfc.h>