use Win32::GuiTest qw/SendKeys IsKeyPressed/;

my @keys = qw/1 2 3 x y z ESC/;
my $logfile = "logfile_eingaben.txt";

open LOGFILE, ">> $logfile";
#until (IsKeyPressed("1")&&("2")) {
until (IsKeyPressed("ESC")) {
    for (@keys) {
        if (IsKeyPressed($_)) {
            print LOG "$_ wurde gedrückt\n";
            SendKeys "{PAUSE 1}";
        }
        elsif (IsKeyPressed("Strg"))
        {
        print LOG " $_ gedrückt\n";
        SendKeys "{PAUSE 1}";
        }
        
        else {
           SendKeys "{PAUSE 1}";
        }
    }
}
close LOGFILE;

use Win32::GuiTest qw/SendKeys IsKeyPressed :VK/;
[...]
       if (IsKeyPressed(VK_SHIFT)) { # bzw. VK_ALT / VK_CONTROL
           print LOG "SHIFT wurde gedrückt\n";
           SendKeys "{PAUSE 1}";
       }
[...]

int findvkey(const char* name, int* key) 
{
    /* symbol table record */
    typedef struct tokentable {
        char *token;
        int vkey;
    } tokentable;

    /* global symbol table */
    static tokentable tbl[]  = {
        "BAC", VK_BACK,
        "BS" , VK_BACK,
        "BKS", VK_BACK,
        "BRE", VK_CANCEL,
        "CAP", VK_CAPITAL,
        "DEL", VK_DELETE,
        "DOW", VK_DOWN,
        "END", VK_END,
        "ENT", VK_RETURN,
        "ESC", VK_ESCAPE,
        "HEL", VK_HELP,
        "HOM", VK_HOME,
        "INS", VK_INSERT,
        "LEF", VK_LEFT,
        "NUM", VK_NUMLOCK,
        "PGD", VK_NEXT,
        "PGU", VK_PRIOR,
        "PRT", VK_SNAPSHOT,
        "RIG", VK_RIGHT,
        "SCR", VK_SCROLL,
        "TAB", VK_TAB,
        "UP",  VK_UP,
        "F1",  VK_F1,
        "F2",  VK_F2,
        "F3",  VK_F3,
        "F4",  VK_F4,
        "F5",  VK_F5,
        "F6",  VK_F6,
        "F7",  VK_F7,
        "F8",  VK_F8,
        "F9",  VK_F9,
        "F10",  VK_F10,
        "F11",  VK_F11,
        "F12",  VK_F12,
        "F13",  VK_F13,
        "F14",  VK_F14,
        "F15",  VK_F15,
        "F16",  VK_F16,
        "F17",  VK_F17,
        "F18",  VK_F18,
        "F19",  VK_F19,
        "F20",  VK_F20,
        "F21",  VK_F21,
        "F22",  VK_F22,
        "F23",  VK_F23,
        "F24",  VK_F24,
    "SPC",  VK_SPACE,
    "SPA",  VK_SPACE,
        "LWI",  VK_LWIN,
        "RWI",  VK_RWIN,
        "APP",  VK_APPS,
    };
    int i;
    for (i=0;i<sizeof(tbl)/sizeof(tokentable);i++) {
        if (strcmp(tbl[i].token, name)==0) {
            *key=tbl[i].vkey;
            return 1;
    }
    }
    return 0;
}

BOOL
IsKeyPressed(name)
    char* name;
    CODE:
    int vkey;
    int found;
    int len = strlen(name);
    if (len >= 3) 
        name[3]=NUL;
    found = findvkey(name, &vkey);
    if (found) {
        OutputDebugString("Trying key\n");
        RETVAL = GetAsyncKeyState(vkey);
    } else if (strlen(name)==1 && (isdigit(*name) || isalpha(*name))) {
        OutputDebugString("Trying alphanum\n");
        RETVAL = GetAsyncKeyState(toupper(*name));
    }else {
        OutputDebugString("No key\n");
        RETVAL = 0;
    }
    OUTPUT:
        RETVAL

int len = strlen(name);
if (len >= 3) 
   name[3]=NUL;

441a442,453
> BOOL IsDigitString(const char *s)
> {
>       if(s == NULL || *s == 0)
>               return FALSE;
>
>       while(*s && isdigit(*s)) {
>               s++;
>       }
>
>       return *s == 0 ? TRUE : FALSE;
> }
>
1503,1504c1515,1516
<     if (len >= 3)
<         name[3]=NUL;
---
>     /*if (len >= 3)
>         name[3]=NUL;*/
1508a1521,1523
>     } else if (IsDigitString(name)) {
>       OutputDebugString("Trying integer\n");
>       RETVAL = GetAsyncKeyState(atoi(name));