Segfaults are not always repeatable. You may have an undefined pointer that sometime points into unreachable or unallocated memory, causing a segfault, and sometimes may point into valid memory, without causing a segfault.
You may want to read https://cran.r-project.org/doc/manuals/r-release/R-exts.html#Checking-memory-access for tips on how to diagnose such problems. HTH, Peter On Sat, Aug 11, 2018 at 2:13 PM Rolf Turner <r.tur...@auckland.ac.nz> wrote: > > I am getting a seg fault from a package that I am working on, and I am > totally flummoxed by it. The fault presumably arises from dynamically > loaded Fortran code, but I'm damned if I can see where the error lies. > > In an effort to diagnose the problem I created a "non-package" version > of the code. That is, I copied all the *.R files and *.f file into a > new directory. In that directory I created a *.so file using > R CMD SHLIB. > > In the R code I removed all the "PACKAGE=" lines from the calls to > .Fortran() and put in appropriate dyn.load() calls. > > I then started R in this new "clean" directory and sourced all of the > *.R files. > > I then issued the command that produces the seg fault when run under the > aegis of the package. The command ran without a murmur of complaint. > WTF? > > Can anyone suggest a reason why a seg fault might arise when the code is > run in the context of a package, but not when it is run in "standalone > mode"? > > I have checked and rechecked my init.c file --- which is the only thing > that I can think of that might create a difference --- and cannot find > any discrepancy between the declarations in the init.c file and the > Fortran code. > > The package is a bit complicated, so giving more detail would be > cumbersome. Also I have no idea what aspects of detail would be > relevant. If anyone would like more info, feel free to ask. > > I would really appreciate it if someone could give me some suggestions > before I go *completely* mad! > > cheers, > > Rolf Turner > > -- > Technical Editor ANZJS > Department of Statistics > University of Auckland > Phone: +64-9-373-7599 ext. 88276 > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
