http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49953
Summary: _toupper() and _tolower() macros in ctype.h are broken
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
AssignedTo: [email protected]
ReportedBy: [email protected]
not sure if I categorized this correctly.
in ctype.h I found
#define _tolower(_Char) ((_Char)-'A'+'a')
#define _toupper(_Char) ((_Char)-'a'+'A')
this code is broken when it is used in the situations where the character is
already in the desired case. then you get garbage characters.
try it yourself.
example: _tolower('a') produces garbage.
#include <ctype.h>
#include <stdio.h>
int main(void) {
printf("%c%c", _toupper('A'),_tolower('a'));
//result is !ΓΌ which is not proper
return 0;
}
a proper bug fix would be
#define _tolower(_Char) ((_Char>='A'&&_Char<='Z')?_Char+('a'-'A'):_Char)
#define _toupper(_Char) ((_Char>='a'&&_Char<='z')?_Char-('a'-'A'):_Char)
//#include <ctype.h>
#include <stdio.h>
#define _tolower(_Char) ((_Char>='A'&&_Char<='Z')?_Char+('a'-'A'):_Char)
#define _toupper(_Char) ((_Char>='a'&&_Char<='z')?_Char-('a'-'A'):_Char)
int main(void) {
printf("%c%c%c%c", _toupper('A'),_toupper('a'),
_tolower('A'),_tolower('a'));
//result is AAaa
return 0;
}
