Front page | perl.perl5.porters |
Postings from April 2000
Alan Burlison <Alan.Burlison@uk.sun.com> writes: >> That is doubly not true: >> 1. The use of bare 'na' etc. has been deprecated since 5.005-ish. >> 2. There is a work round by setting POLLUTE - so compatibility _is_ built in. > >I've worked around this in the past by doing the following: > >#ifndef PL_na >#define PL_na na >#endif > >#ifndef PL_sv_undef >#define PL_sv_undef sv_undef >#endif > >To provide backwards compatibility with old perls. This works fine in >5.005_03, but breaks in 5.6.0. Yes I can see that might be a problem if they are just variables rather than #defines - as it the case for non-threaded non-multiplicity 5.6.0 >What is the correct incantation that >preserves backwards compatibility? The incantation I have in Tk is: #ifndef PATCHLEVEL #include <patchlevel.h> #endif #if defined(PATCHLEVEL) && (PATCHLEVEL < 5) #define PL_sv_undef sv_undef #define PL_stack_base stack_base #define PL_stack_sp stack_sp ... #endif Note that is doubly subtle as PATCHLEVEL itself is now not set by default. And also (because I never want to use perl's na which is just a waste of CPU cycles for somthing you don't want): #ifdef na #if PATCHLEVEL >= 5 #undef na #endif #endif I forget why the PATCHLEVEL test is in that one. > >Alan Burlison -- Nick Ing-Simmons