The company I'm at does two coding interviews for potential developer hires.
The first is kind of a standard phone interview with a Google Doc. There is no expectation that the code you write would actually compile or run. When I conduct this interview I'm always sure to explicitly say that it's not a test of memory and they shouldn't worry about remembering specific standard library functions, etc. If they need something that they know exists but they don't remember the specifics, I encourage them to make up something that seems reasonable and just go with it.
The second is an onsite interview where we plop them at a desktop machine, give them a relatively simple programming task, and ask them to produce a runnable program. They have access to the internet and really the entire machine. They can Google whatever they want and even use Stack Overflow. Nobody is standing there hovering over their shoulder. This interview gets weighted more than the previous one.
The first is kind of a standard phone interview with a Google Doc. There is no expectation that the code you write would actually compile or run. When I conduct this interview I'm always sure to explicitly say that it's not a test of memory and they shouldn't worry about remembering specific standard library functions, etc. If they need something that they know exists but they don't remember the specifics, I encourage them to make up something that seems reasonable and just go with it.
The second is an onsite interview where we plop them at a desktop machine, give them a relatively simple programming task, and ask them to produce a runnable program. They have access to the internet and really the entire machine. They can Google whatever they want and even use Stack Overflow. Nobody is standing there hovering over their shoulder. This interview gets weighted more than the previous one.