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From: cummings@cacr.caltech.edu To: gcc-gnats@gcc.gnu.org Subject: libstdc++/5859: gdb fails to break in C++ MPI code Date: Wed, 06 Mar 2002 19:06:00 -0000 [thread overview] Message-ID: <20020307030348.10776.qmail@sources.redhat.com> (raw) >Number: 5859 >Category: libstdc++ >Synopsis: gdb fails to break in C++ MPI code >Confidential: no >Severity: critical >Priority: medium >Responsible: unassigned >State: open >Class: sw-bug >Submitter-Id: net >Arrival-Date: Wed Mar 06 19:06:01 PST 2002 >Closed-Date: >Last-Modified: >Originator: Julian Cummings >Release: 3.0 >Organization: >Environment: i686 running Linux 2.4.9-ac9 >Description: The gdb debugger fails to break on the symbol MPI_Init in a trivial MPI code written in C++. The code uses the mpich package from Argonne National Laboratory and is compiled using mpiCC, a script that invokes the g++ compiler and links with libmpich.a. The code is executed using "mpirun" and the -gdb flag, which causes gdb to set a breakpoint at MPI_Init and run the program. The problem is triggered by any C++ MPI code that utilizes C++ streams, for example, to write something to std::cout. In this case, the code will run through all of main() and stop inside the global object destructor phase. With no usage of C++ streams, the code halts at MPI_Init as it should. Also, a comparable MPI code written in C functions properly with gdb. I am reporting this as a gcc bug because it does not happen with gcc 2.96. It seems that something has changed with respect to the C++ standard library and streams that makes debugging of MPI codes with gdb no longer possible. >How-To-Repeat: You will need to have a recent version of mpich installed (http://www.mcs.anl.gov/mpi/mpich). I am using mpich-1.2.1. With this installed, build my example code with the command "mpiCC -g -o cctest main.cc". Then run it on a single processor, for example, with the command "mpirun -np 1 ./cctest". Now try to run it under the gdb debugger by adding the flag -gdb to the mpirun command. You should see that the code does not break at MPI_Init as expected. >Fix: >Release-Note: >Audit-Trail: >Unformatted: ----gnatsweb-attachment---- Content-Type: application/octet-stream; name="main.cc" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="main.cc" I2luY2x1ZGUgIm1waS5oIgojaW5jbHVkZSA8aW9zdHJlYW0+CgppbnQgbWFpbihpbnQgYXJnYyxj aGFyICphcmd2W10pIAp7CiAgaW50IG15UElkLCBuUHJvY2Vzc29yczsKICBpbnQgbG9jYWwsIGds b2JhbDsKICBjaGFyIG5hbWVbODBdOwogIGludCBNaW4sIE1heDsKICBpbnQgYSwgYiwgbG9jYWxT aXplOwogIGludCBuLCBpOwoKICBNUElfSW5pdCgmYXJnYywgJmFyZ3YpOwogIE1QSV9Db21tX3Jh bmsoTVBJX0NPTU1fV09STEQsICZteVBJZCk7CiAgTVBJX0NvbW1fc2l6ZShNUElfQ09NTV9XT1JM RCwgJm5Qcm9jZXNzb3JzKTsKCgoKCiAgc3RkOjpjb3V0IDw8IkhlbGxvIHdvcmxkIGZyb20gcHJv Y2Vzc29yOiIgPDwgbXlQSWQgPDwgIiBvZiAiIDw8CiAgICAgIG5Qcm9jZXNzb3JzIDw8ICIgcHJv Y2Vzc29ycyIgPDwgc3RkOjplbmRsOwogIAogIGxvY2FsID0gMDsKCiAgYSA9IDA7IGIgPSAxMDAw OwogIGxvY2FsU2l6ZSA9IChiLWEpIC8gblByb2Nlc3NvcnM7CgogIE1pbiA9IGEgKyBteVBJZCAq IGxvY2FsU2l6ZTsKICBNYXggPSBNaW4gKyBsb2NhbFNpemU7CgogIGZvciAoaSA9IE1pbjsgaSA8 IE1heDsgKytpKSB7CgogICAgbG9jYWwgPSBsb2NhbCArIGk7CiAgfQogIAoKCiAgTVBJX0FsbHJl ZHVjZSgmbG9jYWwsICZnbG9iYWwsIDEsTVBJX0lOVCwgTVBJX1NVTSwgTVBJX0NPTU1fV09STEQp OwoKICBzdGQ6OmNvdXQgPDwgIkxvY2FsIHZhbHVlIG9uIHByb2Nlc3NvcjogIiA8PCBteVBJZCA8 PCAiID0gIiA8PCBsb2NhbCA8PCAiIGdsb2JhbCB2YWx1ZSA9ICIKCSAgICA8PCAgZ2xvYmFsIDw8 IHN0ZDo6ZW5kbDsKICAKICAKICBNUElfRmluYWxpemUoKTsKICByZXR1cm4gMDsKfQo=
next reply other threads:[~2002-03-07 3:06 UTC|newest] Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top 2002-03-06 19:06 cummings [this message] 2002-03-15 20:09 rodrigc 2002-03-18 18:10 rodrigc
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