ISA: Determine whether a variable is of a certain type, class, or structure name.

GET_LOGIN_INFO: Return the name of the computer as well as the user’s login name.

QUERY_ASCII: Obtain information about an ASCII file.

QUERY_BMP: Obtain information about a BMP image file.

QUERY_CSV: Obtain information about a comma-separated values (CSV) file.

QUERY_DICOM: Test file for compatibility with READ_DICOM.

QUERY_GIF: Obtain information about a GIF image file.

QUERY_IMAGE: Determine if a file is an image file.

QUERY_JPEG: Obtain information about a JPEG image file.

QUERY_JPEG2000: Obtain information about a JPEG 2000 image file.

QUERY_MRSID: Obtain information about a MrSID image file.

QUERY_PICT: Obtain information about a PICT image file.

QUERY_PNG: Obtain information about a PNG image file.

QUERY_PPM: Obtain information about a PPM image file.

QUERY_SRF: Obtain information about an SRF image file.

QUERY_TIFF: Obtain information about a TIFF image file.

QUERY_VIDEO: Obtain information about a video file.

QUERY_WAV: Check that the file is actually a .WAV file.

ROUTINE_FILEPATH: Return the full path to a compiled procedure or function.

TYPENAME: Retrieve a variable’s IDL type name, class name, or structure name.