The operation of the framefiles() is determined by two environment
variables: GRASP_FRAMEPATH, and GRASP_REALTIME. If GRASP_REALTIME is set, then the framefiles() interogates the EPICS
control system and returns a pointer to a character string containing the
name of the frame file most recently written to disk. This option is
only intended for use in the 40-meter lab control room, for real-time
analysis of data. For most users of GRASP, this option will never
be used. Note: to set/unset the environment variable, use the commands:
If the GRASP_REALTIME environment variable is NOT set, then the
behavior of framefiles() is determined by the value of the GRASP_FRAMEPATH
environment variable. This variable should point to a directory, and may be set with
a command like:
setenv GRASP_DATAPATH /usr/local/GRASP/data/18nov94.1frame
The first time that framefiles() is called, it looks for all files with names of the type:
in the directory pointed to by GRASP_FRAMEPATH. These correspond, respectively, to Caltech 40-m frame files labeled by date, Caltech 40-m frame files labeled by GPS time, Hanford frame files, Hanford trend frames, Livingston frame files, and Livingston trend frames. Note that the directory should contain files with only one type of label: if several label types exist in the directory, only the files whose type matches the first entry found on the list above will be used. The labeling conventions are explained in Section . The file names are stored internally, framefiles() returns a pointer to a character string containing the name of the first of these files. The second call to framefiles() returns the name of the second file found in the directory, and so on. When no more files remain, framefiles() returns a NULL pointer.
A simple way to analyze a subset of data is to create a directory containing symbolic links to the FRAME files containing data that you want to analyze, and to set the environment variable GRASP_FRAMEPATH to point to that directory.