Re: [ctypes-users] how to handle library interdependencies

[Andrew M. <And...@ac...>]

> -----Original Message-----
> I tried using the following calling syntax to load my=20
> library, which appears to accept the mode argument. However,=20
> I still get the unresolved symbol no matter what I use.=20
> RTLD_LAZY appears to not be accepted as an argument, but even=20
> when I use 1, which is the value RTLD_LAZY is set to in=20
> /usr/include/bits/dlfcn.h, it still fails on the undefined=20
> symbol. Sigh. Any suggestions?

A quick peek in the source for ctypes 1.0 shows that RTLD_NOW is being=20
forced, overriding any attempt to use RTLD_LAZY.

RTLD_LAZY hasn't been defined as a ctypes constant, probably because=20
it isn't being allowed (not all Posix like Oses may support it maybe?).

If you're in a position to recompile/reinstall ctypes:
- comment out the "mode |=3D RTLD_NOW;" at about line 1207 in=20
  source/callproc.c
- at about line 4705 in source/_ctypes.c add "PyModule_AddObject()"
calls=20
  to add definitions for RTLD_LAZY and (for completeness) RTLD_NOW.

Rebuild/reinstall and then call LoadLibrary() with the option set to=20
ctypes.RTLD_GLOBAL | ctypes.RTLD_LAZY

BTW, I presume this is on Linux?  Or Solaris?  The "PrmLic" seems=20
familiar - would the libraries you're having trouble with be part of an=20
ESRI product?  If so, you might be able to find some samples which list=20
the order of the libraries on a linkage command line, which would be a=20
strong hint as to the order you should load the SOs.

Regards,
Andrew.

-------------------------> "These thoughts are mine alone!" <---------
Andrew MacIntyre           National Licensing and Allocations Branch
tel:   +61 2 6219 5356     Inputs to Industry Division
fax:   +61 2 6253 3277     Australian Communications & Media Authority
email: and...@ac...=20