1 files changed, 54 insertions, 0 deletions
diff --git a/libc/ctype/toupper.c b/libc/ctype/toupper.c
new file mode 100644
index 0000000..7977beb
--- /dev/null
+++ b/libc/ctype/toupper.c
@@ -0,0 +1,54 @@
+/*
+FUNCTION
+	<<toupper>>---translate characters to upper case
+
+INDEX
+	toupper
+INDEX
+	_toupper
+
+ANSI_SYNOPSIS
+	#include <ctype.h>
+	int toupper(int <[c]>);
+	int _toupper(int <[c]>);
+
+TRAD_SYNOPSIS
+	#include <ctype.h>
+	int toupper(<[c]>);
+	int _toupper(<[c]>);
+
+
+DESCRIPTION
+<<toupper>> is a macro which converts lower-case characters to upper
+case, leaving all other characters unchanged.  It is only defined when
+<[c]> is an integer in the range <<EOF>> to <<255>>.
+
+You can use a compiled subroutine instead of the macro definition by
+undefining this macro using `<<#undef toupper>>'.
+
+<<_toupper>> performs the same conversion as <<toupper>>, but should
+only be used when <[c]> is known to be a lowercase character (<<a>>--<<z>>).
+
+RETURNS
+<<toupper>> returns the upper-case equivalent of <[c]> when it is a
+character between <<a>> and <<z>>, and <[c]> otherwise.
+
+<<_toupper>> returns the upper-case equivalent of <[c]> when it is a
+character between <<a>> and <<z>>.  If <[c]> is not one of these
+characters, the behaviour of <<_toupper>> is undefined.
+
+PORTABILITY
+<<toupper>> is ANSI C.  <<_toupper>> is not recommended for portable programs.
+
+No supporting OS subroutines are required.
+*/
+
+#include <_ansi.h>
+#include <ctype.h>
+
+#undef toupper
+int
+_DEFUN(toupper,(c),int c)
+{
+  return islower(c) ? c - 'a' + 'A' : c;
+}