**C, <strike>66</strike> 48**

*Original:*

    int l(long*s){return strlen(s)/((*s&~(-1L<<56))!=0x656c676f6f67);}

Using OSX gcc,  
`l("duck");` returns `4`,   
`l("google");` causes `Floating point exception: 8`. 

On other platforms, the constants may need to be adjusted for endianness.

*Shorter*:

  less trickyness, same results.

     l(int*s){return strlen(s)/!!strcmp(s,"Google");}