Daniel Stutzbach wrote:
On Tue, Aug 31, 2010 at 4:54 AM, M.-A. Lemburg <mal@egenix.com> wrote:
Is it possible to have multiple versions of the lib C loaded on Windows ?
Yes, and it's a pretty common situation. The fopen() that I call within a DLL may not be the same fopen() called by another DLL. When writing a DLL for Windows, the API must be designed with the assumption that anything returned by the C library cannot be passed a different C library. For example, suppose I a expose a function in my DLL that allocates some memory, populates it with useful information, and returns a pointer. I must also supply a function to free the memory. I cannot ask the caller to simply call free(), because their free() may not be using the same heap as my malloc().
But isn't exactly that a major problem for Python ? An extension written for a different MS CRT version would not be able to safely free a buffer allocated by the Python DLL.
Likewise, a FILE * isn't safe to pass around, unless I can guarantee that the application really is one big happy family compiled against the same version of the C library.
According to the MS document I found this also applies to the OS environment and handles. Taking all these things together makes it sound like there's a rather small chance of actually getting PEP 384 working across Windows compiler upgrades. Then again, I haven't heard of many people actually running into those possible issues. -- Marc-Andre Lemburg eGenix.com Professional Python Services directly from the Source (#1, Aug 27 2010)
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