truncate(p1)
public
Truncates file to at most integer bytes. The file must be
opened for writing. Not available on all platforms.
f = File.new("out", "w")
f.syswrite("1234567890")
f.truncate(5)
f.close()
File.size("out")
static VALUE
rb_file_truncate(VALUE obj, VALUE len)
{
rb_io_t *fptr;
struct ftruncate_arg fa;
fa.pos = NUM2POS(len);
GetOpenFile(obj, fptr);
if (!(fptr->mode & FMODE_WRITABLE)) {
rb_raise(rb_eIOError, "not opened for writing");
}
rb_io_flush_raw(obj, 0);
fa.fd = fptr->fd;
if ((int)rb_thread_io_blocking_region(nogvl_ftruncate, &fa, fa.fd) < 0) {
rb_sys_fail_path(fptr->pathv);
}
return INT2FIX(0);
#undef NUM2POS
}