[Mingw-users] time_t type and dirent.h functions in WSL 4.0

[Eli Z. <el...@gn...>]

I'm posting this here first because I might be missing something.  If
my observations are correct, and this is a bug, I will open a ticket.

The layout of 'struct dirent' in WSL 4.0 uses the time_t type:

  struct dirent
  {
	  long			d_ino;		/* Always zero. */
	  unsigned short	d_reclen;	/* Always zero. */
	  unsigned short	d_namlen;	/* Length of name in d_name. */

	  /* The following exactly mimic the layout of _finddata_t ...
	   */
	  unsigned		d_type;		/* File attributes */
	  time_t		d_time_create;
	  time_t		d_time_access;	/* always midnight local time */
	  time_t		d_time_write;
	  _fsize_t		d_size;
	  /*
	   * ...so that we may map a union of _finddata_t at the
	   * location of d_type (corresponding to _finddata_t.attrib),
	   * and thus map this directly to the _findfirst/_findnext
	   * returned field.
	   */
	  char			d_name[FILENAME_MAX]; /* File name. */
  };

However, the width of time_t can be either 32 bits or 64 bits, with
the latter being the default in 4.0:

  #if defined(_USE_32BIT_TIME_T)
  typedef	__time32_t time_t;
  #else
  typedef	__time64_t time_t;
  #endif /* _USE_32BIT_TIME_T */

Presumably, when the dirent functions were compiled for inclusion in
the libmingwex library, the compilation used the 64-bit default
definition of time_t.

This means that applications that define _USE_32BIT_TIME_T will use an
incompatible definition of 'struct dirent', which will break any code
that calls the dirent functions.

Am I missing something?  If not, it sounds like 'struct dirent32' and
readdir32 etc. functions will be needed to allow use of both 32-bit
time_t and dirent functions in the same program, similarly to what is
already done with time-related functions, 'stat', etc.