diff --git a/reactos/lib/sdk/crt/crt.rbuild b/reactos/lib/sdk/crt/crt.rbuild
index 26830c649d6..beb485d6ccf 100644
--- a/reactos/lib/sdk/crt/crt.rbuild
+++ b/reactos/lib/sdk/crt/crt.rbuild
@@ -11,8 +11,8 @@
-
- precomp.h
+
+ precomp.h
cgets.c
cprintf.c
@@ -23,6 +23,9 @@
putch.c
ungetch.c
+
+ ctype.c
+
chdir.c
chdrive.c
diff --git a/reactos/lib/sdk/crt/ctype/ctype.c b/reactos/lib/sdk/crt/ctype/ctype.c
new file mode 100644
index 00000000000..c9a542f185e
--- /dev/null
+++ b/reactos/lib/sdk/crt/ctype/ctype.c
@@ -0,0 +1,591 @@
+#include
+#include
+
+#undef _pctype
+
+#define upalpha ('A' - 'a')
+
+
+unsigned short _ctype[] = {
+ 0, /* , 0xFFFF */
+ _CONTROL, /* CTRL+@, 0x00 */
+ _CONTROL, /* CTRL+A, 0x01 */
+ _CONTROL, /* CTRL+B, 0x02 */
+ _CONTROL, /* CTRL+C, 0x03 */
+ _CONTROL, /* CTRL+D, 0x04 */
+ _CONTROL, /* CTRL+E, 0x05 */
+ _CONTROL, /* CTRL+F, 0x06 */
+ _CONTROL, /* CTRL+G, 0x07 */
+ _CONTROL, /* CTRL+H, 0x08 */
+ _CONTROL | _SPACE, /* CTRL+I, 0x09 */
+ _CONTROL | _SPACE, /* CTRL+J, 0x0a */
+ _CONTROL | _SPACE, /* CTRL+K, 0x0b */
+ _CONTROL | _SPACE, /* CTRL+L, 0x0c */
+ _CONTROL | _SPACE, /* CTRL+M, 0x0d */
+ _CONTROL, /* CTRL+N, 0x0e */
+ _CONTROL, /* CTRL+O, 0x0f */
+ _CONTROL, /* CTRL+P, 0x10 */
+ _CONTROL, /* CTRL+Q, 0x11 */
+ _CONTROL, /* CTRL+R, 0x12 */
+ _CONTROL, /* CTRL+S, 0x13 */
+ _CONTROL, /* CTRL+T, 0x14 */
+ _CONTROL, /* CTRL+U, 0x15 */
+ _CONTROL, /* CTRL+V, 0x16 */
+ _CONTROL, /* CTRL+W, 0x17 */
+ _CONTROL, /* CTRL+X, 0x18 */
+ _CONTROL, /* CTRL+Y, 0x19 */
+ _CONTROL, /* CTRL+Z, 0x1a */
+ _CONTROL, /* CTRL+[, 0x1b */
+ _CONTROL, /* CTRL+\, 0x1c */
+ _CONTROL, /* CTRL+], 0x1d */
+ _CONTROL, /* CTRL+^, 0x1e */
+ _CONTROL, /* CTRL+_, 0x1f */
+ _SPACE | _BLANK, /* ` ', 0x20 */
+ _PUNCT, /* `!', 0x21 */
+ _PUNCT, /* 0x22 */
+ _PUNCT, /* `#', 0x23 */
+ _PUNCT, /* `$', 0x24 */
+ _PUNCT, /* `%', 0x25 */
+ _PUNCT, /* `&', 0x26 */
+ _PUNCT, /* 0x27 */
+ _PUNCT, /* `(', 0x28 */
+ _PUNCT, /* `)', 0x29 */
+ _PUNCT, /* `*', 0x2a */
+ _PUNCT, /* `+', 0x2b */
+ _PUNCT, /* `,', 0x2c */
+ _PUNCT, /* `-', 0x2d */
+ _PUNCT, /* `.', 0x2e */
+ _PUNCT, /* `/', 0x2f */
+ _DIGIT | _HEX, /* `0', 0x30 */
+ _DIGIT | _HEX, /* `1', 0x31 */
+ _DIGIT | _HEX, /* `2', 0x32 */
+ _DIGIT | _HEX, /* `3', 0x33 */
+ _DIGIT | _HEX, /* `4', 0x34 */
+ _DIGIT | _HEX, /* `5', 0x35 */
+ _DIGIT | _HEX, /* `6', 0x36 */
+ _DIGIT | _HEX, /* `7', 0x37 */
+ _DIGIT | _HEX, /* `8', 0x38 */
+ _DIGIT | _HEX, /* `9', 0x39 */
+ _PUNCT, /* `:', 0x3a */
+ _PUNCT, /* `;', 0x3b */
+ _PUNCT, /* `<', 0x3c */
+ _PUNCT, /* `=', 0x3d */
+ _PUNCT, /* `>', 0x3e */
+ _PUNCT, /* `?', 0x3f */
+ _PUNCT, /* `@', 0x40 */
+ _UPPER | _HEX, /* `A', 0x41 */
+ _UPPER | _HEX, /* `B', 0x42 */
+ _UPPER | _HEX, /* `C', 0x43 */
+ _UPPER | _HEX, /* `D', 0x44 */
+ _UPPER | _HEX, /* `E', 0x45 */
+ _UPPER | _HEX, /* `F', 0x46 */
+ _UPPER, /* `G', 0x47 */
+ _UPPER, /* `H', 0x48 */
+ _UPPER, /* `I', 0x49 */
+ _UPPER, /* `J', 0x4a */
+ _UPPER, /* `K', 0x4b */
+ _UPPER, /* `L', 0x4c */
+ _UPPER, /* `M', 0x4d */
+ _UPPER, /* `N', 0x4e */
+ _UPPER, /* `O', 0x4f */
+ _UPPER, /* `P', 0x50 */
+ _UPPER, /* `Q', 0x51 */
+ _UPPER, /* `R', 0x52 */
+ _UPPER, /* `S', 0x53 */
+ _UPPER, /* `T', 0x54 */
+ _UPPER, /* `U', 0x55 */
+ _UPPER, /* `V', 0x56 */
+ _UPPER, /* `W', 0x57 */
+ _UPPER, /* `X', 0x58 */
+ _UPPER, /* `Y', 0x59 */
+ _UPPER, /* `Z', 0x5a */
+ _PUNCT, /* `[', 0x5b */
+ _PUNCT, /* 0x5c */
+ _PUNCT, /* `]', 0x5d */
+ _PUNCT, /* `^', 0x5e */
+ _PUNCT, /* `_', 0x5f */
+ _PUNCT, /* 0x60 */
+ _LOWER | _HEX, /* `a', 0x61 */
+ _LOWER | _HEX, /* `b', 0x62 */
+ _LOWER | _HEX, /* `c', 0x63 */
+ _LOWER | _HEX, /* `d', 0x64 */
+ _LOWER | _HEX, /* `e', 0x65 */
+ _LOWER | _HEX, /* `f', 0x66 */
+ _LOWER, /* `g', 0x67 */
+ _LOWER, /* `h', 0x68 */
+ _LOWER, /* `i', 0x69 */
+ _LOWER, /* `j', 0x6a */
+ _LOWER, /* `k', 0x6b */
+ _LOWER, /* `l', 0x6c */
+ _LOWER, /* `m', 0x6d */
+ _LOWER, /* `n', 0x6e */
+ _LOWER, /* `o', 0x6f */
+ _LOWER, /* `p', 0x70 */
+ _LOWER, /* `q', 0x71 */
+ _LOWER, /* `r', 0x72 */
+ _LOWER, /* `s', 0x73 */
+ _LOWER, /* `t', 0x74 */
+ _LOWER, /* `u', 0x75 */
+ _LOWER, /* `v', 0x76 */
+ _LOWER, /* `w', 0x77 */
+ _LOWER, /* `x', 0x78 */
+ _LOWER, /* `y', 0x79 */
+ _LOWER, /* `z', 0x7a */
+ _PUNCT, /* `{', 0x7b */
+ _PUNCT, /* `|', 0x7c */
+ _PUNCT, /* `}', 0x7d */
+ _PUNCT, /* `~', 0x7e */
+ _CONTROL, /* 0x7f */
+ 0, /* 0x80 */
+ 0, /* 0x81 */
+ 0, /* 0x82 */
+ 0, /* 0x83 */
+ 0, /* 0x84 */
+ 0, /* 0x85 */
+ 0, /* 0x86 */
+ 0, /* 0x87 */
+ 0, /* 0x88 */
+ 0, /* 0x89 */
+ 0, /* 0x8a */
+ 0, /* 0x8b */
+ 0, /* 0x8c */
+ 0, /* 0x8d */
+ 0, /* 0x8e */
+ 0, /* 0x8f */
+ 0, /* 0x90 */
+ 0, /* 0x91 */
+ 0, /* 0x92 */
+ 0, /* 0x93 */
+ 0, /* 0x94 */
+ 0, /* 0x95 */
+ 0, /* 0x96 */
+ 0, /* 0x97 */
+ 0, /* 0x98 */
+ 0, /* 0x99 */
+ 0, /* 0x9a */
+ 0, /* 0x9b */
+ 0, /* 0x9c */
+ 0, /* 0x9d */
+ 0, /* 0x9e */
+ 0, /* 0x9f */
+ 0, /* 0xa0 */
+ 0, /* 0xa1 */
+ 0, /* 0xa2 */
+ 0, /* 0xa3 */
+ 0, /* 0xa4 */
+ 0, /* 0xa5 */
+ 0, /* 0xa6 */
+ 0, /* 0xa7 */
+ 0, /* 0xa8 */
+ 0, /* 0xa9 */
+ 0, /* 0xaa */
+ 0, /* 0xab */
+ 0, /* 0xac */
+ 0, /* 0xad */
+ 0, /* 0xae */
+ 0, /* 0xaf */
+ 0, /* 0xb0 */
+ 0, /* 0xb1 */
+ 0, /* 0xb2 */
+ 0, /* 0xb3 */
+ 0, /* 0xb4 */
+ 0, /* 0xb5 */
+ 0, /* 0xb6 */
+ 0, /* 0xb7 */
+ 0, /* 0xb8 */
+ 0, /* 0xb9 */
+ 0, /* 0xba */
+ 0, /* 0xbb */
+ 0, /* 0xbc */
+ 0, /* 0xbd */
+ 0, /* 0xbe */
+ 0, /* 0xbf */
+ 0, /* 0xc0 */
+ 0, /* 0xc1 */
+ 0, /* 0xc2 */
+ 0, /* 0xc3 */
+ 0, /* 0xc4 */
+ 0, /* 0xc5 */
+ 0, /* 0xc6 */
+ 0, /* 0xc7 */
+ 0, /* 0xc8 */
+ 0, /* 0xc9 */
+ 0, /* 0xca */
+ 0, /* 0xcb */
+ 0, /* 0xcc */
+ 0, /* 0xcd */
+ 0, /* 0xce */
+ 0, /* 0xcf */
+ 0, /* 0xd0 */
+ 0, /* 0xd1 */
+ 0, /* 0xd2 */
+ 0, /* 0xd3 */
+ 0, /* 0xd4 */
+ 0, /* 0xd5 */
+ 0, /* 0xd6 */
+ 0, /* 0xd7 */
+ 0, /* 0xd8 */
+ 0, /* 0xd9 */
+ 0, /* 0xda */
+ 0, /* 0xdb */
+ 0, /* 0xdc */
+ 0, /* 0xdd */
+ 0, /* 0xde */
+ 0, /* 0xdf */
+ 0, /* 0xe0 */
+ 0, /* 0xe1 */
+ 0, /* 0xe2 */
+ 0, /* 0xe3 */
+ 0, /* 0xe4 */
+ 0, /* 0xe5 */
+ 0, /* 0xe6 */
+ 0, /* 0xe7 */
+ 0, /* 0xe8 */
+ 0, /* 0xe9 */
+ 0, /* 0xea */
+ 0, /* 0xeb */
+ 0, /* 0xec */
+ 0, /* 0xed */
+ 0, /* 0xee */
+ 0, /* 0xef */
+ 0, /* 0xf0 */
+ 0, /* 0xf1 */
+ 0, /* 0xf2 */
+ 0, /* 0xf3 */
+ 0, /* 0xf4 */
+ 0, /* 0xf5 */
+ 0, /* 0xf6 */
+ 0, /* 0xf7 */
+ 0, /* 0xf8 */
+ 0, /* 0xf9 */
+ 0, /* 0xfa */
+ 0, /* 0xfb */
+ 0, /* 0xfc */
+ 0, /* 0xfd */
+ 0, /* 0xfe */
+ 0 /* 0xff */
+};
+
+unsigned short *_pctype = _ctype + 1;
+unsigned short *_pwctype = _ctype + 1;
+
+/*
+ * @implemented
+ */
+unsigned short **__p__pctype(void)
+{
+ return &_pctype;
+}
+
+/*
+ * @implemented
+ */
+unsigned short **__p__pwctype(void)
+{
+ return &_pwctype;
+}
+
+int _isctype (int c, int ctypeFlags)
+{
+ return (_pctype[(unsigned char)(c & 0xFF)] & ctypeFlags);
+}
+
+/*
+ * @implemented
+ */
+int iswctype(wint_t wc, wctype_t wctypeFlags)
+{
+ return (_pwctype[(unsigned char)(wc & 0xFF)] & wctypeFlags);
+}
+
+/*
+ * obsolete
+ *
+ * @implemented
+ */
+int is_wctype(wint_t wc, wctype_t wctypeFlags)
+{
+ return (_pwctype[(unsigned char)(wc & 0xFF)] & wctypeFlags);
+}
+
+/*
+ * @implemented
+ */
+int isalpha(int c)
+{
+ return(_isctype(c, _ALPHA));
+}
+
+/*
+ * @implemented
+ */
+int isalnum(int c)
+{
+ return(_isctype(c, _ALPHA | _DIGIT));
+}
+
+/*
+ * @implemented
+ */
+int iswalnum(wint_t c)
+{
+ return iswctype(c, _ALPHA | _DIGIT);
+}
+
+/*
+ * @implemented
+ */
+int __isascii(int c)
+{
+ return ((unsigned char)c <= 0x7f);
+}
+
+/*
+ * @implemented
+ */
+int iswascii(wint_t c)
+{
+ return __isascii(c);
+}
+
+/*
+ * @implemented
+ */
+int iscntrl(int c)
+{
+ return(_isctype(c, _CONTROL));
+}
+
+/*
+ * @implemented
+ */
+int __iscsym(int c)
+{
+ return(isalnum(c)||(c == '_'));
+}
+
+/*
+ * @implemented
+ */
+int __iscsymf(int c)
+{
+ return(isalpha(c)||(c == '_'));
+}
+
+/*
+ * @implemented
+ */
+int isdigit(int c)
+{
+ return(_isctype(c, _DIGIT));
+}
+
+/*
+ * @implemented
+ */
+int isgraph(int c)
+{
+ return (_isctype (c, _PUNCT | _ALPHA | _DIGIT));
+}
+
+/*
+ * @implemented
+ */
+int islower(int c)
+{
+ return (_isctype (c, _LOWER));
+}
+
+/*
+ * @implemented
+ */
+int isprint(int c)
+{
+ return (_isctype (c, _BLANK | _PUNCT | _ALPHA | _DIGIT));
+}
+
+/*
+ * @implemented
+ */
+int ispunct(int c)
+{
+ return (_isctype (c, _PUNCT));
+}
+
+/*
+ * @implemented
+ */
+int isspace(int c)
+{
+ return (_isctype (c, _SPACE));
+}
+
+/*
+ * @implemented
+ */
+int isupper(int c)
+{
+ return (_isctype (c, _UPPER));
+}
+
+/*
+ * @implemented
+ */
+int isxdigit(int c)
+{
+ return (_isctype (c, _HEX));
+}
+
+
+/*
+ * @implemented
+ */
+int iswalpha(wint_t c)
+{
+ return (iswctype (c, _ALPHA));
+}
+
+/*
+ * @implemented
+ */
+int iswcntrl(wint_t c)
+{
+ return iswctype(c, _CONTROL);
+}
+
+/*
+ * @implemented
+ */
+int iswdigit(wint_t c)
+{
+ return (iswctype (c, _DIGIT));
+}
+
+/*
+ * @implemented
+ */
+int iswgraph(wint_t c)
+{
+ return iswctype(c,_PUNCT | _ALPHA | _DIGIT);
+}
+
+/*
+ * @implemented
+ */
+int iswprint(wint_t c)
+{
+ return iswctype((unsigned short)c,_BLANK | _PUNCT | _ALPHA | _DIGIT);
+}
+
+
+/*
+ * @implemented
+ */
+int iswpunct(wint_t c)
+{
+ return iswctype(c, _PUNCT);
+}
+
+/*
+ * @implemented
+ */
+int iswlower(wint_t c)
+{
+ return (iswctype (c, _LOWER));
+}
+
+/*
+ * @implemented
+ */
+int iswupper(wint_t c)
+{
+ return iswctype(c, _UPPER);
+}
+
+
+/*
+ * @implemented
+ */
+int iswspace(wint_t c)
+{
+ return (iswctype (c, _SPACE));
+}
+
+/*
+ * @implemented
+ */
+int iswxdigit(wint_t c)
+{
+ return (iswctype (c, _HEX));
+}
+
+
+/*
+ * @implemented
+ */
+int __toascii(int c)
+{
+ return((unsigned)(c) & 0x7f);
+}
+
+/*
+ * @implemented
+ */
+int _tolower(int c)
+{
+ if (_isctype (c, _UPPER))
+ return (c - upalpha);
+ return(c);
+}
+
+/*
+ * @implemented
+ */
+int _toupper(int c)
+{
+ if (_isctype (c, _LOWER))
+ return (c + upalpha);
+ return(c);
+}
+
+/*
+ * @implemented
+ */
+int tolower(int c)
+{
+ if (_isctype (c, _UPPER))
+ return (c - upalpha);
+ return(c);
+}
+
+/*
+ * @implemented
+ */
+int toupper(int c)
+{
+ if (_isctype (c, _LOWER))
+ return (c + upalpha);
+ return(c);
+}
+
+/*
+ * @implemented
+ */
+wchar_t towlower(wchar_t c)
+{
+ if (iswctype (c, _UPPER))
+ return (c - upalpha);
+ return(c);
+}
+
+/*
+ * @implemented
+ */
+wchar_t towupper(wchar_t c)
+{
+ if (iswctype (c, _LOWER))
+ return (c + upalpha);
+ return(c);
+}
+
+/* EOF */