Meaning of open_fds field of fdtable

Question

i'm trying to write a system call that close all files of a process.

Can anyone explain me what is the bitmap returned from

fd->open_fds[n]

where fd is a pointer to fdtable and n is an int.

thanks

Answer 1

i've had that trouble too because i need it for a syscall. The open_fds field of fdt table contains initially the address of open_fds_init field, and this one is a bitmap that constains the file descriptors of currently opened files.