C:\Temp>echo package FooTempTest;warn __PACKAGE__; 1; > FooTempTest.pm

C:\Temp>perl -MFooTempTest -e 1
FooTempTest at FooTempTest.pm line 1.

C:\Temp>cacls.EXE FooTempTest.pm /E /D %username%
processed file: C:\Temp\FooTempTest.pm

C:\Temp>more FooTempTest.pm
Cannot access file C:\Temp\FooTempTest.pm

C:\Temp>perl -e" eval {require FooTempTest; 1} or die qq{($@)($!)($^E)
+}"
(Can't locate FooTempTest.pm in @INC (@INC contains: C:/Perl/site/lib 
+C:/Perl/lib .) at -e l
ine 1.
)(Permission denied)(Access is denied) at -e line 1.
[download]

Unfortunately, there's no guarantee the error code is related to the problem. That would be fine if that was our only tool, but previously suggested strace provides the same data more accurately.

Are you sure? Looking at the source of the message, I think you can

3531     SAVECOPFILE_FREE(&PL_compiling);

3532     CopFILE_set(&PL_compiling, tryrsfp ? tryname : name);

3533     SvREFCNT_dec(namesv);

3534     if (!tryrsfp) {

3535         if (PL_op->op_type == OP_REQUIRE) {

3536             const char *msgstr = name;

3537             if(errno == EMFILE) {

3538                 SV * const msg

3539                     = sv_2mortal(Perl_newSVpvf(aTHX_ "%s:   %s", 
+msgstr,

3540                                                Strerror(errno)));

3541                 msgstr = SvPV_nolen_const(msg);

3542             } else {

3543                 if (namesv) {                   /* did we lookup 
+@INC? */

3544                     AV * const ar = GvAVn(PL_incgv);

3545                     I32 i;

3546                     SV * const msg = sv_2mortal(Perl_newSVpvf(aTH
+X_ 

3547                         "%s in @INC%s%s (@INC contains:",

3548                         msgstr,

3549                         (instr(msgstr, ".h ")

3550                          ? " (change .h to .ph maybe?)" : ""),

3551                         (instr(msgstr, ".ph ")

3552                          ? " (did you run h2ph?)" : "")

3553                                                               ));

3554                     

3555                     for (i = 0; i <= AvFILL(ar); i++) {

3556                         sv_catpvs(msg, " ");

3557                         sv_catsv(msg, *av_fetch(ar, i, TRUE));

3558                     }

3559                     sv_catpvs(msg, ")");

3560                     msgstr = SvPV_nolen_const(msg);

3561                 }    

3562             }

3563             DIE(aTHX_ "Can't locate %s", msgstr);

3564         }
[download]

strace is fine, but since it already gives an error message, maybe it should also include Strerror(errno))?