I was the interviewer. I am interested in seeing if they know what is on their resume. To do this, I ask about 30-45 minutes of technical questions about C, Unix, and SQL (Oracle) with two or three programming exercises.

On Unix, you have a program that worked fine with your unit testing and in QA. When it got to Production, it crashed horribly within ten hours after processing, say, ten million requests. How do you approach such a situation?

"I am sorry for asking such an elementary question, but we have to ask." In C, what is the difference between strcpy and memcpy? Have you used memmove? How is that different from memcpy?

In Unix, what are some ways to communicate between two processes?

Have you dealt with alignment? Given a structure:

struct { char c; int ii; } var;

How big is var?

Have you dealt with swapping when sending data between little-endian and big-endian machines? Where?

Here are two tables. Please write a SELECT statement that will pull these columns from that table and those columns from this table. How would the query change if we needed an outer join?

On Unix, you just downloaded a few hundred files from another system to a new directory, and the names are all uppercase. You want to rename all the files to lowercase. You want to keep the contents of the files the same but change the names to lowercase. What do you do?

I always ask: we need a C function to do some string manipulation. We just moved from another system where this was part of the standard library, and it is not there on this system. Here is the prototype; please implement this for us. The exact details change, but it involves adding and/or removing strings from an input string. If you have done much C string manipulation, it won't cause any trouble. If not, you will crash and burn, and it will be very obvious.