# PL_HashTableLookup

Looks up the entry with the specified key and return its value.

## Syntax

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

void *PL_HashTableLookup(
  PLHashTable *ht,
  const void *key);
```

### Parameters

The function has the following parameters:

`ht`

: A pointer to the hash table in which to look up the entry specified
  by `key`.

`key`

: A pointer to the key for the entry to look up.

### Returns

The value of the entry with the specified key, or `NULL` if there is
no such entry.

## Description

If there is no entry with the specified key, {ref}`PL_HashTableLookup`
returns `NULL`. This means that one cannot tell whether a `NULL`
return value means the entry does not exist or the value of the entry is
`NULL`. Keep this ambiguity in mind if you want to store `NULL`
values in a hash table.