io_readfile - open a file for reading

       io_readfile sets d to the number of a new descriptor reading from the disk file named s, and returns 1.

       If  something goes wrong, io_readfile sets errno to indicate the error, and returns 0; it does not create
       a new descriptor, and it does not touch d.

       io_readfile - open a file for reading

io_createfile(3), io_appendfile(3), io_readwritefile(3)

                                                                                                  io_readfile(3)

#include<libowfat/io.h>

       int io_readfile(int64* d,const char* s);