ASM allowed in Fortran? and OpenDir?

[Tobias Burnus]

Hi Fx,

FX Coudert wrote:
> According to my linux man page, you forgot the d_type member:
>           struct dirent {
>               ino_t          d_ino;       /* inode number */
>               off_t          d_off;       /* offset to the next dirent */
>               unsigned short d_reclen;    /* length of this record */
>               unsigned char  d_type;      /* type of file */
>               char           d_name[256]; /* filename */
>           };
Could well be, but it fails already much earlier:
  dir = opendir (&"."[1]{lb: 1 sz: 1}, 1);
returns a NULL pointer whereas C's
  dir = opendir ((const char *) (char *) ".");
returns a non-NULL pointer.

(errno is probably not the right variable; in C errno is a macro which
returns "*__errno_location ()".)

> And, the whole point of this is: there is no portable way to do this.
> POSIX only says "the structure dirent which includes the following
> members: ino_t  d_ino, file serial number; char   d_name[], name of
> entry". This information is enough to be used in C, but not in Fortran
> which needs to know the complete layout of the structure. This is one
> of the reasons why I'm not convinced that ISO_C_BINDING leads to
> enhanced portability...
It does, but by far it does not solve all problems; if one controls both
parts of the program - the C and the Fortran part - then it helps a lot.
For opendir/readdir one should probably write a C wrapper.

Tobias