The type of file determines the medium on which the file is located (e.g., disk or network) and, hence, which internal device driver is used by CFITSIO to read and/or write the file. Currently supported types are
file:// - file on local magnetic disk (default)
ftp:// - a readonly file accessed with the anonymous FTP protocol.
It also supports ftp://username:password@hostname/...
for accessing password-protected ftp sites.
http:// - a readonly file accessed with the HTTP protocol. It
supports username:password just like the ftp driver.
Proxy HTTP servers are supported using the http_proxy
environment variable (see following note).
stream:// - special driver to read an input FITS file from the stdin
stream, and/or write an output FITS file to the stdout
stream. This driver is fragile and has limited
functionality (see the following note).
gsiftp:// - access files on a computational grid using the gridftp
protocol in the Globus toolkit (see following note).
root:// - uses the CERN root protocol for writing as well as
reading files over the network.
shmem:// - opens or creates a file which persists in the computer's
shared memory.
mem:// - opens a temporary file in core memory. The file
disappears when the program exits so this is mainly
useful for test purposes when a permanent output file
is not desired.
If the filetype is not specified, then type file:// is assumed.
The double slashes '//' are optional and may be omitted in most cases.