# V3517\. AUTOSAR\. The functions from time\.h/ctime should not be used\.

This diagnostic rule is based on the software development guidelines developed by [AUTOSAR](https://www.autosar.org/) \(AUTomotive Open System ARchitecture\)\.

The analyzer issues this warning when it detects the following functions: 'clock', 'time', 'difftime', 'ctime', 'asctime', 'gmtime', 'localtime', 'mktime'\.

These functions have unspecified or implementation\-dependent behavior, so they may return time and date in different formats \(depending on the environment, implementation of the standard library, and so on\)\.

Here is an example of code triggering this warning:

```cpp
const char* Foo(time_t *p)
{
    time_t t = time(p);
    return ctime(t);
}
```