With your code running on proprietory hardware, there is no way for us to predict what facilities may be available to perform this task.

Most CPU's have very accurate hardware timers, and most OS's provide means to access them.

Whether such facilities are available on the embedded system in question is something only you can answer.

Well, the device runs embedded Linux on a PPC processor, if that helps.

I can't use modules

Why not? What's the specific restriction you're dealing with? Site policy? Lack of install permissions? Lack of a compiler? Or... what?

If it's just a distribution problem, consider downloading Time::HiRes and copying bits of its source code into your program...

The code is going to be running on an proprietary embedded device. To add software to the image that it runs requires me to pay a hefty sum of money. It has perl already, but no modules.

If you can't compile libraries, I think you're limited to the time() function and its one second accuracy. (You might be able to qx() out to a command-line program that returned the time with hundredths of a second precision, but that'd probably take long enough that it would throw off your timing.

Update: Or, as mpeppler points out, you could use syscall(). It sounds like your manufacturer probably didn't include the headers or syscall.ph, but if they did this would be a good workaround.

then you should consider getting rid of this proprietary device and going for something else. this kind of restrictiveness is like have a 10 ton block of cement chained to your ankle; you will never be able to get anywhere or do anything while you are still tied to it!

So you have Perl, but no modules. I suspect that you will soon begin to conclude the Perl is a pain to program with. If you aren't going to be able to take advantage of the CPAN, then there seems to be very little sense in having Perl installed at all. It sounds to me like it would be much more to your advantage to program with a lower-level langauge, like C.

So you have Perl, but no modules. I suspect that you will soon begin to conclude the Perl is a pain to program with

I'll have to disagree here - while CPAN is incredibly useful, you're still going to be much more productive coding in perl than in C even without access to it, and by using the syscall() built-in you can achieve pretty much anything that you need for low-level system functions. It's much more work than using various perl modules from CPAN, but it should get you there.

Michael

For the most part perl covers our needs wonderfully...cases like this are the exception. We don't have a C compiler either (they make you buy an SDK for that), so perl is more or less our only choice.

If you don't have a C compiler, then you are going to have a hard time solving this problem. Presumably, the operating system has a function that give the time with a higher accuracy than the Perl builtin time(). Calling the C API from Perl requires an XS module compiled by a C compiler.

The Time::HiRes module provides an interface to the gettimeofday function that will do the job. But you can't compile it because you don't have a C compiler. And can't install Perl modules.

Time::HiRes contains an XS component which requires a C-compiler, header files etc.

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