[Bug c++/17556] New: linker fails to find template

["igodard at pacbell dot net" <gcc-bugzilla at gcc dot gnu dot org>]

The attached .tar.gz dile explodes to the following:

1) a -v -save-temps compile of the library module "bitset.cc"; the compiler 
output is "foolib", the save-temps is "bitset.ii".

2) a -v -save-temps of a compile of a test case "testBitset.cc" that uses the 
library; the compiler output is "foowithlib" and the save-temnps is 
"testBitset.iiwithlib". This fails to link because the linker cannot file a 
template (operator<<) that is located in "bitset.cc".

3) a -v -save-temps of the same testcase modified to explicitly include the 
source of "bitset.cc" inline rather than picking it up from the library. This 
compiles and links OK, verifying that definition of the template in the 
"bitset.c" does in fact satisfy the calls in the test case.

4) the binary "libs.a" which includes the result of compiling "bitset.cc" and 
some other libraries. The linker does find other itams from that library even 
when it fails to find the template in question, verifying that the link-time 
file lookup is finding the library correctly. This binary is required to get the  
testcase to link without error; however, you can link without it and ignore all 
errors except the one shown in the failing link output.

My workaround is to make the template in question be an inline in the .hh file 
(in which case everything compiles and links fine). However, it's not a small 
function and the multiple inlines do cause code bloat in my application. I 
intend to see if an explicit instantiation will also workaround, but haven't done it yet.

Ivan

-- 
           Summary: linker fails to find template
           Product: gcc
           Version: 3.4.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: igodard at pacbell dot net
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17556