[patch, fortran] Separate READ from WRITE

[Jerry DeLisle]

On 10/12/2010 01:58 AM, Tobias Burnus wrote:
> On 10/11/2010 08:57 PM, Tobias Burnus wrote:
>> Thomas Koenig wrote:
>>> Well, feedback seems to have been positive, so here is the formal patch
>>> with a proper changelog entry.
>>
>> No review yet but:
>>
>> iocall[IOCALL_X_LOGICAL] = gfc_build_library_function_decl_with_spec (
>> get_identifier (PREFIX("transfer_logical")), ".wW",
>> void_type_node, 3, dt_parm_type, pvoid_type_node, gfc_int4_type_node);
>>
>> + iocall[IOCALL_X_LOGICAL_WRITE] = gfc_build_library_function_decl_with_spec (
>> + get_identifier (PREFIX("transfer_logical_write")), ".rW",
>> + void_type_node, 3, dt_parm_type, pvoid_type_node, gfc_int4_type_node);
>> +
>
> I looked at libgfortran/io/transfer.c and both formatted_transfer_scalar_read
> and -_write contain a like like:
> dtp->u.p.sf_read_comma =
> dtp->u.p.current_unit->decimal_status == DECIMAL_COMMA ? 0 : 1;

I don't know if this is relevant but parameters within the current_unit 
structure can and do get modified by read and write functions. Bits within the 
"common" structure get modified at run time by the error and iostat, err, end, 
eor events, but are not used from one IO call to the next. They are checked by 
series of calls between st_write/read and st_write_done/read_done to check 
library status as the various transfers proceed.

I am wondering as part of the ABI cleanup, should we isolate the function 
arguments so that it is clear which ones get modified and which do not?

Jerry