$bool = is_FH($fh);
$bool = is_FH(\*FH);
This is just a (more intuitively named) alias for is_arg_ok().
Returns 1 if its argument is an open filehandle.
Returns 0 if its argument is something other than an open filehandle.
$bool = is_arg_ok($fh);
$bool = is_arg_ok(\*FH);
Returns 1 if its argument is an open filehandle.
Returns 0 if its argument is something other than an open filehandle.
Arguments to the following functions must be open filehandles. If
any of those functions receive an argument that is not an open
filehandle then the function dies with an appropriate error message.
To ensure that your script won't suffer such a death, you could first
check by passing the argument to is_FH(). Or you could wrap the
function call in an eval{} block.
Note that it may be possible that a filehandle opened for writing may
become unwritable. If for example the disk runs full on Linux, a write
attempt will fail, while is_W($fh) still reports true. The behavior
for other platforms is not tested.
$bool = is_R($fh);
$bool = is_R(\*FH);
Returns true if the filehandle is readable.
Else returns false.
$bool = is_W($fh);
$bool = is_W(\*FH);
Returns true if the filehandle is writable.
Else returns false.
$bool = is_RO($fh);
$bool = is_RO(\*FH);
Returns true if the filehandle is readable but not writable.
Else returns false.
$bool = is_WO($fh);
$bool = is_WO(\*FH);
Returns true if the filehandle is writable but not readable.
Else returns false.
$bool = is_RW($fh);
$bool = is_RW(\*FH);
Returns true if the filehandle is both readable and writable.
Else returns false.
$bool = is_A($fh);
$bool = is_A(\*FH);
Returns true if the filehandle was opened for appending.
Else returns false.
Not currently implemented on Win32 with pre-5.6.1 versions of perl (and
dies with appropriate error message if called on such a platform).