I have an "EXSYS EX-1341 Convert-Module USB – parallel", OpenSuSE 11 found it as /dev/usblp0.

cat /proc/ioports | grep parport
0378-037a : parport0
0778-077a : parport0

But this programm doesn't work and has no error messages:
#include <stdio.h>
#include <unistd.h>
#include <sys/io.h>
#include <sys/resource.h>

int main()
{

/* lp0 onboard works
if (ioperm(0x378,1,1) == -1)
perror("Error in ioperm()");
else
outb(0x55,0x378);
return 0;
*/

if (ioperm(0x778,1,1) == -1)
perror("Error in ioperm()");
else
outb(0x55,0x778);
return 0;
}

Nothing happens, no reaction on the parallel pins, what's wrong or missing ?

(Or is the module just crap, who knows a working one ?)