[GRASS-dev] [GRASS GIS] #2748: ctype.POINTER function overloading prevents automatic byref() conversion

[GRASS GIS]

#2748: ctype.POINTER function overloading prevents automatic byref() conversion
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  Reporter:  artegion       |      Owner:  grass-dev@…
      Type:  defect         |     Status:  new
  Priority:  normal         |  Milestone:
 Component:  Python ctypes  |    Version:  7.0.1
Resolution:                 |   Keywords:
       CPU:  Unspecified    |   Platform:  Unspecified
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Comment (by artegion):

 Replying to [comment:1 glynn]:
 > Replying to [ticket:2748 artegion]:
 >
 > > grass.lib module overwrites ctype.POINTER function in ctypes_preamble
 module.
 >
 > The replacement POINTER function has the following comment:
 > {{{
 >     # Convert None to a real NULL pointer to work around bugs
 >     # in how ctypes handles None on 64-bit platforms
 > }}}
 > Have you tested whether this is still an issue (it might have been fixed
 since ctypesgen was last updated)?
 >
 > Having to use byref() explicitly seems less of an issue than not working
 on 64-bit systems.
 >
 > Actually, if an argument is a pointer, the caller should probably be
 using byref() explicitly regardless of whether or not ctypes has a
 workaround. What's the problem with needing to use byref()?

 Not a real problem, just a bit disappointing: python ctypes documentation
 describes an interesting feature but our code presents a different
 behavior (it is far more pythonic do not care about byreference/byvalue if
 ctypes can do the dirty work).

 The odd thing is that happens unnoticed: while ctypes raises exceptions
 passing wrong argument type in this case only function return code (or
 segmentation fault exception) reveals troubles.

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Ticket URL: <https://trac.osgeo.org/grass/ticket/2748#comment:4>
GRASS GIS <https://grass.osgeo.org>