# PRTimeParamFn

This type defines a callback function to calculate and return the time
parameter offsets from a calendar time object in GMT.

## Syntax

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

typedef PRTimeParameters (PR_CALLBACK_DECL *PRTimeParamFn)
   (const PRExplodedTime *gmt);
```

## Description

The type {ref}`PRTimeParamFn` represents a callback function that, when
given a time instant in GMT, returns the time zone information (offset
from GMT and DST offset) at that time instant.