Why do compile times change?

[Hal Vaughan]

I've noticed that when I'm fine tuning a class, I seem to get a quick
compile time. Then, if I have to compile another class with a change, it
takes much longer to compile. The next time I compile the 2nd class, it
compiles quickly.

Does the compiler do anything like track changes in files or use previous
compile output while compiling a file a 2nd or third time?

If not, why is there a difference in compile times? It's long enough I
would think it's not just a disk-buffering issue.

Hal

[Jeff Schwab]

Hal Vaughan wrote:

I've noticed that when I'm fine tuning a class, I seem to get a quick
compile time. Then, if I have to compile another class with a change, it
takes much longer to compile. The next time I compile the 2nd class, it
compiles quickly.

Does the compiler do anything like track changes in files or use previous
compile output while compiling a file a 2nd or third time?

If not, why is there a difference in compile times? It's long enough I
would think it's not just a disk-buffering issue.

Hal

You are very observant. :) Your OS (and probably your hard disk) are
doing the caching.

[nos]

"Jeff Schwab" <je******@comcast.net> wrote in message
news:yN********************@comcast.com...

Hal Vaughan wrote:

I've noticed that when I'm fine tuning a class, I seem to get a quick
compile time. Then, if I have to compile another class with a change, it takes much longer to compile. The next time I compile the 2nd class, it
compiles quickly.

Does the compiler do anything like track changes in files or use previous compile output while compiling a file a 2nd or third time?

If not, why is there a difference in compile times? It's long enough I
would think it's not just a disk-buffering issue.

Hal

You are very observant. :) Your OS (and probably your hard disk) are
doing the caching.

you can always check the time the class file was created