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[Frama-c-discuss] Printing all global variables of a set of C files?

On Mon, Sep 30, 2013 at 5:35 PM, Virgile Prevosto
<virgile.prevosto at m4x.org>wrote:

> >   * I have a variable "v" erroneously defined in two C files (a.c and
> > b.c): what is the expected behaviour of a C compiler and Frama-C in
> > such a case?
> As often with the C standard, nothing is completely clear. (references
> below are made against C99):
> Following 6.2.2?5, and ?2, as long as v is not explicitely declared
> static in one of the files, it should refer to the same object after
> link. In addition, it should not be initialized explicitely in both
> files (as per 6.9?5).
> That said, 6.9.2?2 seems to indicate that if you only have int v; in a
> file (without an explicit extern declaration), it should be treated as
> int v = 0;, so that you would end up with a variable defined in both
> a.c and b.c.
> A quick check suggests that neither gcc nor clang does the latter: as
> long as v is explicitely initialized in at most one file, they will
> link the program and use this initializer, as does Frama-C.
>

This is a common compiler extension, listed as ?J.5.11 Multiple external
definitions? in the standard itself. This was discussed in this
StackOverflow question:

http://stackoverflow.com/questions/1490693/tentative-definitions-in-c99-and-linking
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