In C how do I print filename of file that is redirected as input in shell

Question

$cc a.c
$./a.out < inpfilename

I want to print inpfilename on stdout. How do I do that ? Thanks for the help in advance...

Answer 1

In fact, it is possible to get filename from procfs, since /proc/*/fd contains symlink to opened files:

char filename[bufsize];
int sz = readlink("/proc/self/fd/0", filename, bufsize-1);
filename[sz] = 0;
puts(filename);