Re: [boost] Boost regex with optimizations doesn't link

From: Yitzhak Sapir (Yitzhak.Sapir_at_[hidden])
Date: 2008-03-11 09:05:56

> > I guess my mail program (Outlook) reduplicates the > g++ on every new
> > line when it splits up the lines.  Sorry about this.
> >
g++ -I sources/3rdParty/boost -I sources/3rdParty/local-config/linux/
-Lsources/3rdParty/releases/linux/debug -lboost_regex test.cpp [works]

g++ -I sources/3rdParty/boost -I sources/3rdParty/local-config/linux/
-Lsources/3rdParty/releases/linux/release -lboost_regex test.cpp
[gives above error]

> Well.... the obvious mistake is that the library name must occur *after* the source file that uses it.

> Does this help?

Not really.  The library name must occur after all libraries that use that library (that is, order of
decreasing dependency).  But in this case I'm compiling a small cpp directly into an a.out.
The cpp name is the input to the compiler and should be placed after all options, including the
options that g++ is expected to pass to the linker.  Your answer further does not explain
why the corresponding and similar command line works with the debug version of the library.

I have seen problems like this in cases of wrong inline instantiations.  I remember a similar
problem in Visual Studio with an exported (inline) template function in an exported class,
where the client user of the shared library expects to import a function, but obviously the
compiler couldn't generate the template function instantiation when creating the dll, and so
there is a resulting import of a nonexistent function -- an undefined reference.   This seems
to be a related problem, except that in g++ 3.3.3 there is no control of export declarations
that I know of.  In Visual Studio, the problem would be solved by making the class non-
exported, and specifying for the specific necessary functions within the class the export
declaration.  Also, if this were a result of inlining, it would explain why the problem does
not appear in debug.

Yitzhak Sapir

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