How to find where a file resides.

How can I determine where a file physically resides?

I.E. Is is actually located in a package, spill-file or on a regular file
sysetm, and if so, which one.

I need to know this both from C code and using standard utilities.

Standard utility way would be ‘pkgctl fullpath’. There should be some
devctl code for that, ask Thomas.

Bill at Sierra Design wrote:

How can I determine where a file physically resides?

I.E. Is is actually located in a package, spill-file or on a regular file
sysetm, and if so, which one.

I need to know this both from C code and using standard utilities.