Thread: Why does this not work when passed through a function?

You need to pass the size of the array as another parameter.
sizeof(buff) does NOT do what you want. It just tells you the size of the pointer, not how much space it points to.

Not to mention that the second variant doesn't actually work correctly, as it returns an address to a local variable that is gone (as in destroyed) by the time you actually get back to the function calling it. It may appear like it's actually working, but it is just the same fluke that can get you across a junction against a red light - if you are lucky, there's nothing coming the other way.

Doing this:

Code:

char* getValue(usb_device_handle* h, usb_device* dev)
{
      char value[ 256 ];
      usb_get_string_simple( h, dev->descriptor.iManufacturer, value, sizeof( value ) );
      return value;
}

void foo()
{
   char dummy[256] = { 0 };
   memset(dummy, 0x33, sizeof(dummy)-2);
}

int main()
{
...
   char *val = getValue(...);
   foo();
   printf("val = %s\n", val);
..
}

will show how it DOESN'T work.

--
Mats