D.Wakeling@exeter.ac.uk wrote:

To: hugs-bugs@haskell.org Subject: bug in Classic Hugs Feb 2000

Hello, I believe there is a bug in Classic Hugs version Feb 2000. On my Red Hat 6.2 PC, the manual page for fgetpos(3) says:

RETURN VALUES The rewind function returns no value. Upon successful completion, fgetpos, fseek, fsetpos return 0, and ftell returns the current offset.

Yet in the function primFun(primHGetPosn) in the file hugs98/src/iomonad.c there are the lines:

primFun(primHGetPosn) { /* Get file position */ Int h; HandleArg(h,3); if (handles[h].hmode!=HCLOSED) { #if HAVE_FGETPOS fpos_t pos; if (fgetpos(handles[h].hfp,&pos)) { /* <---- WRONG! --- */ IOReturn(mkInt((Int)pos)); } #elif HAVE_FTELL /* A reasonable approximation for pre-ANSI compilers */ long pos = ftell(handles[h].hfp); IOReturn(mkInt((Int)pos)); #else /* deliberate fall through to IOFail */ #endif

The line indicated as "WRONG" above should be

if (fgetpos(handles[h].hfp,&pos) == 0) {

The use of fsetpos(3) looks similarly wrong.

The use of fsetpos/fgetpos was wrong for other reasons (note the blithe coercion to int of the fpos_t value). That code has already been thrown out in the CVS version of hugs98 in favor of the not perfect, but certainly more portable, ftell. But thanks for the report! --Jeff