diff --git a/sys/include/ape/stdio.h b/sys/include/ape/stdio.h
index c961a5da1..defa3ac1f 100644
--- a/sys/include/ape/stdio.h
+++ b/sys/include/ape/stdio.h
@@ -106,7 +106,7 @@ extern int getchar(void);
 #define	getchar()	getc(stdin)
 extern char *gets(char *);
 extern int putc(int, FILE *);
-#define	putc(c, f) ((f)->wp>=(f)->rp?_IO_putc(c, f):(*(unsigned char*)(f)->wp++=(c)&_IO_CHMASK))
+#define	putc(c, f) ((f)->wp>=(f)->rp?_IO_putc(c, f):(int)(*(unsigned char*)(f)->wp++=(c)&_IO_CHMASK))
 extern int _IO_putc(int, FILE *);
 extern int putchar(int);
 #define	putchar(c)	putc(c, stdout)
diff --git a/sys/include/stdio.h b/sys/include/stdio.h
index 39f3b73e7..0daae2f48 100644
--- a/sys/include/stdio.h
+++ b/sys/include/stdio.h
@@ -92,7 +92,7 @@ int getchar(void);
 #define	getchar()	getc(stdin)
 char *gets(char *);
 int putc(int, FILE *);
-#define	putc(c, f) ((f)->wp>=(f)->rp?_IO_putc(c, f):(*(unsigned char*)(f)->wp++=(c)&_IO_CHMASK))
+#define	putc(c, f) ((f)->wp>=(f)->rp?_IO_putc(c, f):(int)(*(unsigned char*)(f)->wp++=(c)&_IO_CHMASK))
 int _IO_putc(int, FILE *);
 int putchar(int);
 #define	putchar(c)	putc(c, stdout)