Conference vaxaxp::vmsnotes

121.0. "LIB$FIND_FILE with a default spec returns files more than once" by OPCO::TSG_PLL (Live and Sweaty) Thu Jan 30 1997 22:17

Folks,

   I am trying to use LIB$FIND_FILE to expand a wildcard filespec that will be
input by a user.  I also want to provide a default spec.  If the default spec is
something like SYS$LOGIN:LOGIN.COM then all is fine.  If the default spec is
SYS$MANAGER:LOGIN.COM and I supply a wildcard filespec then each file that
satisfies the wildcard spec is returned twice.  If the default spec is
SYS$STARTUP:LOGIN.COM then each file is returned four times.
   What am I doing wrong?  Each filespec returned by the call of LIB$FIND_FILE
is then processed and I really only want to process each file once, so how do I
persuade LIB$FIND_FILE to give me each file spec once?

   I have tried the following code on OpenVMS V6.2 Alpha and VAX as well as
OpenVMS V7.1 Alpha.  The DECC compiler version is V5.3-006 in all cases.  If
have also use C++ V5.5 with the same result.


Thanks in advance
Paul

(14:13) $ set verify
(14:13) $ cc/vers nl:
DEC C V5.3-006 on OpenVMS Alpha V7.1    
(14:13) $ cc test
(14:13) $ link test
(14:13) $ run test
LIB$FIND_FILE returns TSG_ROOT:[TSG_PLL]LOGIN.COM;19
LIB$FIND_FILE returns TSG_ROOT:[TSG_PLL]LOGIN.COM;19
(14:13) $ dir sys$login:login*

Directory TSG_ROOT:[TSG_PLL]

LOGIN.COM;19        LOGIN.COM;18        LOGIN.COM;17        

Total of 3 files.
(14:13) $ type test.c
// TEST.C
//

#include    descrip
#include    stdio
#include    ints
#include    lib$routines
#include    rmsdef
#include    string

main (int argc, char *argv[])
{
    struct dsc$descriptor next_file;
    int32   status;
    uint32  find_context=0, rms_status, find_flags=2;
    $DESCRIPTOR  (infile_name,"sys$login:login*");
    $DESCRIPTOR (default_spec, "sys$manager:login.com");
    char    temp[256];
    char    next_file_buff[256];

    next_file.dsc$w_length=255;
    next_file.dsc$b_dtype=DSC$K_DTYPE_T;
    next_file.dsc$b_class=DSC$K_CLASS_S;
    next_file.dsc$a_pointer = next_file_buff;
    while (RMS$_NORMAL == lib$find_file(&infile_name,
                                        &next_file,
                                        &find_context,
                                        &default_spec,
                                        0,
                                        &rms_status,
                                        &find_flags)) {
        strncpy (temp, next_file.dsc$a_pointer, next_file.dsc$w_length);
        temp[next_file.dsc$w_length] = '\0';
        printf("LIB$FIND_FILE returns %s\n", temp);
    }
    lib$find_file_end(&find_context);
}

  Paul,

    SYS$MANAGER is a search list which leads to 2 directories, SYS$STARTUP
  leads to 4. RMS defaulting rules result in the file being found multiple
  times. There's a "good" reason why it works like this, but the behavior
  can cause problems under some circumstances (such as an apparently infinite
  loop when linking).

    There's not a lot you can do about it short of avoiding search list 
  logical names in default filespecs.
						John Gillings, Sydney CSC

    re .0
    
    Also, forget your code. DIRECTORY does exactly the same thing. It's
    expected, if annoying, behaviour and I think the "good" reason for it is
    lost in the mists of time.