strcat Vs strncat - When should which function be used?

Question

Some static code analyzer tools are suggesting that all strcat usage should be replaced with strncat for safety purpose?

In a program, if we know clearly the size of

Answer 1

If you are absolutely sure about source buffer's size and that the source buffer contains a NULL-character terminating the string, then you can safely use strcat when the destination buffer is large enough.

I still recommend using strncat and give it the size of the destination buffer - length of the destination string - 1

Note: I edited this since comments noted that my previous answer was horribly wrong.