(j3.2006) Namelist output

Bill Long longb
Tue Jan 13 12:04:28 EST 2009

John Reid wrote:
> Bill Long wrote:
>> John Reid wrote:
>>> J3,
>>> It has been pointed out to me that the standard is not clear on 
>>> acceptable forms of namelist output for a structure and that compilers 
>>> are inconsistent as to whether they provide the name and a list of 
>>> values of the components or a list of component designators, each 
>>> followed by a value. My correspondent strongly prefers the latter.
>>> In 10.10.2 of F2003, we have: "The form of the output produced is the 
>>> same as that required for input, except for the forms of real, 
>>> character, and logical values.". This suggests that using component 
>>> designators is OK, but says "The name of each namelist group 
>>> object list item is placed in the output record followed by an equals 
>>> and a list of values of the namelist group object list item.".
>> This last sentence does not seem ambiguous to me.  A namelist group 
>> object is a well defined syntax term (R564, page 109 of 09-007).
> Agreed. If this was intended, the sentence at the start of 10.10.2 is wrong. 

That sentence says that the output looks like valid input.  Are you 
saying that for

type t
   real x
   real y
end type

type(t) :: z

if the namelist object is z then it is legal in an input data record to 

  ... z%x = 1.0,  z%y = 2.0 ...

instead of z followed by two real constants?  I don't see where that is 
allowed in the standard.


> These words are unchanged from f90 and I remember then that the i/o group was 
> inclined to say 'name' when they meant 'name or designator'. I would like to 
> know if everyone is agreed that compilers that use component designators in 
> namelist output are non-conforming. Or did we intend that this be an allowed 
> option?
> Cheers,
> John.
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Bill Long                                   longb at cray.com
Fortran Technical Support    &              voice: 651-605-9024
Bioinformatics Software Development         fax:   651-605-9142
Cray Inc., 1340 Mendota Heights Rd., Mendota Heights, MN, 55120


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