5 files changed, 14 insertions, 3 deletions
diff --git a/src/ctype/iscntrl.c b/src/ctype/iscntrl.c
index eead7f5f..9d295d26 100644
--- a/src/ctype/iscntrl.c
+++ b/src/ctype/iscntrl.c
@@ -14,7 +14,7 @@ int iscntrl(int c)
 	RETURN(0, ARGUMENT(c) is not a control character);
 	*/
 
-	return map[c] == 0 || (map[c] == CT_SPACE && c != ' ');
+	return map[c] & CT_CNTRL;
 }
 
 /***
diff --git a/src/ctype/isgraph.c b/src/ctype/isgraph.c
index 206a09b7..ecf88a34 100644
--- a/src/ctype/isgraph.c
+++ b/src/ctype/isgraph.c
@@ -14,7 +14,7 @@ int isgraph(int c)
 	RETURN(0, ARGUMENT(c) is not a graphic character);
 	*/
 
-	return map[c] & ~CT_SPACE;
+	return map[c] & CT_GRAPH;
 }
 
 /***
diff --git a/src/ctype/isprint.c b/src/ctype/isprint.c
index 19847118..41ed6bcf 100644
--- a/src/ctype/isprint.c
+++ b/src/ctype/isprint.c
@@ -14,7 +14,7 @@ int isprint(int c)
 	RETURN(0, ARGUMENT(c) is not a printable character);
 	*/
 
-	return map[c] & ~CT_SPACE || c == ' ';
+	return map[c] & CT_PRINT;
 }
 
 /***
diff --git a/src/ctype/tolower.c b/src/ctype/tolower.c
index 793de6bb..7ef5057a 100644
--- a/src/ctype/tolower.c
+++ b/src/ctype/tolower.c
@@ -1,4 +1,5 @@
 #include <ctype.h>
+#include "stdio.h"
 #include "limits.h"
 #include "nonstd/assert.h"
 #include "nonstd/ctype.h"
@@ -14,6 +15,10 @@ int tolower(int c)
 	RETURN_FAILURE(ARGUMENT(c), ARGUMENT(c) was not an uppercase letter or it has no equivalent lowercase letter);
 	*/
 
+	if (c == EOF) {
+		return EOF;
+	}
+
 	return map[c];
 }
 
diff --git a/src/ctype/toupper.c b/src/ctype/toupper.c
index 35b7c9e2..4844a702 100644
--- a/src/ctype/toupper.c
+++ b/src/ctype/toupper.c
@@ -1,4 +1,5 @@
 #include <ctype.h>
+#include "stdio.h"
 #include "limits.h"
 #include "nonstd/assert.h"
 #include "nonstd/ctype.h"
@@ -13,6 +14,11 @@ int toupper(int c)
 	RETURN_SUCCESS(ARGUMENT(c) converted to uppercase);
 	RETURN_FAILURE(ARGUMENT(c), ARGUMENT(c) was not a lowercase letter or it has no equivalent upercase letter);
 	*/
+
+	if (c == EOF) {
+		return EOF;
+	}
+
 	return map[c];
 }