I am working in three directories:
ownlib90/
home
work/

In ownlib90, I have written a function called iband.f90 which contains
the statement
OPEN (1,file='band.dat',status='old',action='read')
The source file compiles OK, and iband.o is in the archive file of
object files. I assumed that the data file data.dat should be in
the same directrory as the function that uses it, that is, ownlib90,
but this is apparently not the case.

In work/ I have a program that uses the function iband, and when I
run it, I get "file not found, band.dat". It works if I put the data
file into work/ but this is not convenient because I want to be able
to call iband from different directories.

So I put the data file into the home directory into its subdirectory
data/ and changed the OPEN statement to
OPEN (1,file='$home/data/band.dat',status='old',action='read')
I get the same error. I tried $HOME and ~/ but none of these works.

So, leaving the data file in home/data/, what should I put into the
Open statement?

--
Dieter Britz

On Wednesday, August 30, 2023 at 7:53:56 AM UTC-4, db wrote:
> I am working in three directories:
> ownlib90/
> home
> work/
>
> In ownlib90, I have written a function called iband.f90 which contains
> the statement
> OPEN (1,file='band.dat',status='old',action='read')
> The source file compiles OK, and iband.o is in the archive file of
> object files. I assumed that the data file data.dat should be in
> the same directrory as the function that uses it, that is, ownlib90,
> but this is apparently not the case.
The open statement looks in the current directory regardless of where the program executable is stored. Shell expansions (~,*,?) are not available. So probably you want to specify the full filepath as "/home/data/band.dat" but you might find that "../data/band.dat" also works, depending on what the current directory is.

Daniel Feenberg

On 30.08.2023 14.19, Daniel Feenberg wrote:
> On Wednesday, August 30, 2023 at 7:53:56 AM UTC-4, db wrote:
>> I am working in three directories:
>> ownlib90/
>> home
>> work/
>>
>> In ownlib90, I have written a function called iband.f90 which contains
>> the statement
>> OPEN (1,file='band.dat',status='old',action='read')
>> The source file compiles OK, and iband.o is in the archive file of
>> object files. I assumed that the data file data.dat should be in
>> the same directrory as the function that uses it, that is, ownlib90,
>> but this is apparently not the case.
> The open statement looks in the current directory regardless of where the program executable is stored. Shell expansions (~,*,?) are not available. So probably you want to specify the full filepath as "/home/data/band.dat" but you might find that "../data/band.dat" also works, depending on what the current directory is.
>
> Daniel Feenberg
Fortran runtime error: Cannot open file '/home/data/band.dat': No such
file or directory

In the directory I am in, I tried

~/rect2> ls /home/data

and get

ls: cannot access '/home/data': No such file or directory

So that is another variant that doesn't work.

ls ~/data

works, but not inside the OPEN statement.
What now?
--
Dieter Britz

On 30.08.2023 14.58, db wrote:
> On 30.08.2023 14.19, Daniel Feenberg wrote:
>> On Wednesday, August 30, 2023 at 7:53:56 AM UTC-4, db wrote:
>>> I am working in three directories:
>>> ownlib90/
>>> home
>>> work/
>>>
>>> In ownlib90, I have written a function called iband.f90 which contains
>>> the statement
>>> OPEN (1,file='band.dat',status='old',action='read')
>>> The source file compiles OK, and iband.o is in the archive file of
>>> object files. I assumed that the data file data.dat should be in
>>> the same directrory as the function that uses it, that is, ownlib90,
>>> but this is apparently not the case.
>> The open statement looks in the current directory regardless of where
>> the program executable is stored.  Shell expansions (~,*,?) are not
>> available. So probably you want to specify the full filepath as
>> "/home/data/band.dat" but you might find that "../data/band.dat" also
>> works, depending on what the current directory is.
>>
>> Daniel Feenberg
> Fortran runtime error: Cannot open file '/home/data/band.dat': No such
> file or directory
>
> In the directory I am in, I tried
>
> ~/rect2> ls /home/data
>
> and get
>
> ls: cannot access '/home/data': No such file or directory
>
> So that is another variant that doesn't work.
>
> ls ~/data
>
> works, but not inside the OPEN statement.
> What now?

I realised that i am the user db on /home/, so I put in
/home/db/data/band.dat and it finally works. Phew!
That doesn't explain why ~/ and $home/ don't, but
that's academic now.

--
Dieter Britz

On Wednesday, August 30, 2023 at 3:04:05 PM UTC+2, db wrote:
> On 30.08.2023 14.58, db wrote:
> > On 30.08.2023 14.19, Daniel Feenberg wrote:
> >> On Wednesday, August 30, 2023 at 7:53:56 AM UTC-4, db wrote:
> >>> I am working in three directories:
> >>> ownlib90/
> >>> home
> >>> work/
> >>>
> >>> In ownlib90, I have written a function called iband.f90 which contains
> >>> the statement
> >>> OPEN (1,file='band.dat',status='old',action='read')
> >>> The source file compiles OK, and iband.o is in the archive file of
> >>> object files. I assumed that the data file data.dat should be in
> >>> the same directrory as the function that uses it, that is, ownlib90,
> >>> but this is apparently not the case.
> >> The open statement looks in the current directory regardless of where
> >> the program executable is stored. Shell expansions (~,*,?) are not
> >> available. So probably you want to specify the full filepath as
> >> "/home/data/band.dat" but you might find that "../data/band.dat" also
> >> works, depending on what the current directory is.
> >>
> >> Daniel Feenberg
> > Fortran runtime error: Cannot open file '/home/data/band.dat': No such
> > file or directory
> >
> > In the directory I am in, I tried
> >
> > ~/rect2> ls /home/data
> >
> > and get
> >
> > ls: cannot access '/home/data': No such file or directory
> >
> > So that is another variant that doesn't work.
> >
> > ls ~/data
> >
> > works, but not inside the OPEN statement.
> > What now?
> I realised that i am the user db on /home/, so I put in
> /home/db/data/band.dat and it finally works. Phew!
> That doesn't explain why ~/ and $home/ don't, but
> that's academic now.
>
> --
> Dieter Britz
Tilde expansion and environment variables are properties of the shell that you use. They are not automatically expanded within a program ;).

Regards,

Arjen

On 8/30/23 9:29 AM, Arjen Markus wrote:
> Tilde expansion and environment variables are properties of the shell that you use. They are not automatically expanded within a program ;).

A fortran programmer can do the expansion using the standard intrinsic
function GET_ENVIRONMENT_VARIABLE(). Here is the gfortran description,
which coincidentally includes an example with the HOME variable.

https://gcc.gnu.org/onlinedocs/gfortran/GET_005fENVIRONMENT_005fVARIABLE.html

You would generally combine the returned value with the filename to get
the full path name, and then use that in the fortran open statement.

$.02 -Ron Shepard

On Wednesday, August 30, 2023 at 7:29:47 AM UTC-7, Arjen Markus wrote:

(snip)

> Tilde expansion and environment variables are properties of the shell that you use. They are not automatically expanded within a program ;).
A few programs, other than shells, also do it.

Both ~/ and $HOME also work in commands inside vi (and vim).
I suspect also in some other popular Unix-like editors.

Some programs also use specific environment variables for finding files.

AWK has AWKPATH for a path (list of directories) to search for program files.

In all those cases, it is done specifically by the program, not automatically
by the I/O library routines.