cap5: Load libCap5.so from lib/perl/<perl-version>/<perl-archname>

This allows the same version of Base to be used from both RHEL5 and RHEL6
for example; they use different Perl versions which are not compatible at
the ABI level.

documentation/RELEASE_NOTES.html

@@ -13,6 +13,22 @@
 
 <!-- Insert new items immediately below here ... -->
 
+<h4>Path for Cap5 loadable library changed</h4>
+
+<p>The perl CA module makes use of a loadable library, which used to be loaded
+from the base/lib/&lt;host-arch&gt; directory.  However different versions of
+Perl require different loadable library binaries as the Perl ABI can change.
+Now the library will be installed into and loaded from the directory
+base/lib/perl/&lt;version&gt;/&lt;archname&gt; where both &lt;version&gt; and
+&lt;archname&gt; are taken from the Perl configuration.  This makes it possible
+for the same Perl script to be run on both RHEL5 and RHEL6 workstations say, even
+though they use different versions of Perl.</p>
+
+<p>To achieve that, first build EPICS Base using the older OS version.  Then
+on a machine running the newer version, go into the base/src/cap5 directory and
+run a <tt>make rebuild</tt> command.  This will rebuild the libCap5.so file and
+install it into the location appropriate for its Perl version and architecture.</p>
+
 <h4>Build configurations updated for Apple iOS targets</h4>
 
 <p>The build process can now construct universal binaries containing both ARMv6

src/cap5/CA.pm

@@ -6,9 +6,6 @@ use warnings;
 
 my $version = '0.4';
 
-exists $ENV{EPICS_HOST_ARCH}
-    or die "EPICS_HOST_ARCH environment variable not set";
-
 
 package CA;
 
@@ -26,12 +23,17 @@ package Cap5;
 our $VERSION = $version;
 our @ISA = qw(DynaLoader);
 
+# Library is specific to the Perl version and archname
+use Config;
+my $perl_version  = $Config::Config{version};
+my $perl_archname = $Config::Config{archname};
+
 require DynaLoader;
 
 # Add our lib/<arch> directory to the shared library search path
 use File::Basename;
 my $Lib = dirname(__FILE__);
-push @DynaLoader::dl_library_path, "$Lib/../$ENV{EPICS_HOST_ARCH}";
+push @DynaLoader::dl_library_path, "$Lib/$perl_version/$perl_archname";
 
 bootstrap Cap5 $VERSION;
 

src/cap5/Makefile

@@ -22,6 +22,11 @@ ifneq ($(findstring darwin,$(T_A)),)
   LOADABLE_SHRLIB_SUFFIX = .bundle
 endif
 
+PERL_VERSION = $(shell $(PERL) ../perlConfig.pl version)
+PERL_ARCHNAME = $(shell $(PERL) ../perlConfig.pl archname)
+PERL_ARCHPATH = $(PERL_VERSION)/$(PERL_ARCHNAME)
+
+ifeq ($(findstring Host,$(VALID_BUILDS)),Host)
 ifeq ($(findstring $(OS_CLASS),WIN32 cygwin32),)
   # Doesn't build on WIN32
   LOADABLE_LIBRARY_HOST = Cap5
@@ -33,12 +38,11 @@ ifeq ($(findstring $(OS_CLASS),WIN32 cygwin32),)
   PERL_SCRIPTS += camonitor.pl
 
   PERL_MODULES += CA.pm
+  PERL_MODULES += $(PERL_ARCHPATH)/$(LOADABLE_SHRLIB_PREFIX)Cap5$(LOADABLE_SHRLIB_SUFFIX)
 
-  ifeq ($(findstring Host,$(VALID_BUILDS)),Host)
-    # Can only create docs in Host build
-    HTMLS_DIR = .
-    HTMLS = CA.html
-  endif
+  HTMLS_DIR = .
+  HTMLS = CA.html
+endif
 endif
 
 Cap5_SRCS = Cap5.xs
@@ -59,6 +63,10 @@ ifdef T_A
 	$(RM) $@
 	podchecker $< && pod2html --infile=$< --outfile=$@
 
+  $(INSTALL_PERL_MODULES)/$(PERL_ARCHPATH)/%: %
+	$(ECHO) "Installing loadable shared library $@"
+	@$(INSTALL_LIBRARY) -d -m $(LIB_PERMISSIONS) $< $(INSTALL_PERL_MODULES)/$(PERL_ARCHPATH)
+
   clean::
 	$(RM) Cap5.c
 endif