# PRThreadPrivateDTOR

The destructor function passed to PR_NewThreadPrivateIndex that is
associated with the resulting thread private index.

## Syntax

```{code}
#include <prthread.h>

typedef void (PR_CALLBACK *PRThreadPrivateDTOR)(void *priv);
```

### Description

Until the data associated with an index is actually set with a call to
{ref}`PR_SetThreadPrivate`, the value of the data is `NULL`. If the data
associated with the index is not `NULL`, NSPR passes a reference to
the data to the destructor function when the thread terminates.