Strings in C stop at the very first \0, everything after it you can ignore. Your debugger prints the whole array regardless, ignorant of what its contents represent. Filenames cannot contain \0 unless you've got an egregious filesystem bug, anyway.

I wonder if the filename is somehow being mangled when being passed between program to program. I wonder if the name were fed direct from di->d_name to unlink(), whether it would take.

If you try this, try it with extreme caution! I suggest as a start, this to avoid non-semicolon filenames:

Code:

#include <string.h>
...

if(strchr(de->d_name, ';') == NULL) continue;