Re: how to get the file name

Måns Rullgård wrote: 
"Nils O. Selåsdal" <NOS@xxxxxxx> writes:

Tim Keck wrote:
Nils O. Selåsdal wrote: 
marsarden wrote:

only has the FILE * handle , how to get the file name ?

for example,i have a function accpet a (FILE *)argumment and return the
file name : char * getfilename(FILE * fp);

You cannot.
Remember the filename when you opened it, if you can.

(though linux has some not always reliable way, get
the filedescriptor with the fileno() function ,
call the readlink function on the /proc/self/fd/<fd>
fd file. Do a ls -l /proc/self/fd to see what it's about)

One of the beauties of the design is that there is a many to one
relationship between directory entries and files, so a given file
may have many names.

All one could do was remember the filename when it's opened.
plan 9 added the fd2path system call, where the kernel
remembers the original path when it is opened.


What happens if the file is renamed/deleted and replaced with a
different file while it is open?


You get the name. What you do with it is your business, if the name
later on points to a different file, though luck, or perhaps that's
exactly what you expect.

(It should be noted that plan 9 has wildly different sematics for
what happens when you delete a file than what unix has)

.

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