Modify how API version numbers are handled. Update comments and keep

SLURM_API_VERSION parameter in sync with library version numbers built
using libtool.

META

@@ -12,6 +12,6 @@
   Micro:        5
   Version:	0.3.5
   Release:	1
-  API_CURRENT:	1
-  API_AGE:      0
-  API_REVISION: 3
+  API_CURRENT:	5	
+  API_AGE:	4
+  API_REVISION:	0

auxdir/slurm.m4

@@ -115,21 +115,31 @@ AC_SUBST(PROJECT)
 PACKAGE=$PROJECT
 
 ## Build the API version
-SLURM_API_VERSION="0x"
+## NOTE: We map API_MAJOR to be (API_CURRENT - API_AGE) to match the
+##  behavior of libtool in setting the library version number. For more
+##  information see src/api/Makefile.am
 for name in CURRENT REVISION AGE; do
    API=`perl -ne "print,exit if s/^\s*API_$name:\s*(\S*).*/\1/i" $srcdir/META`
    eval SLURM_API_$name=$API
-   API=`printf "%02x" $API`
-   SLURM_API_VERSION="${SLURM_API_VERSION}$API"
 done
+SLURM_API_VERSION="0x"
+SLURM_API_MAJOR=`expr $SLURM_API_CURRENT - $SLURM_API_AGE`
+API=`printf "%02x" $SLURM_API_MAJOR`
+SLURM_API_VERSION="${SLURM_API_VERSION}$API"
+API=`printf "%02x" $SLURM_API_AGE`
+SLURM_API_VERSION="${SLURM_API_VERSION}$API"
+API=`printf "%02x" $SLURM_API_REVISION`
+SLURM_API_VERSION="${SLURM_API_VERSION}$API"
 AC_DEFINE_UNQUOTED(SLURM_API_VERSION, $SLURM_API_VERSION, [Define the API's version])
 AC_DEFINE_UNQUOTED(SLURM_API_CURRENT,  $SLURM_API_CURRENT,  [API current version])
-AC_DEFINE_UNQUOTED(SLURM_API_REVISION, $SLURM_API_REVISION, [API current rev])
+AC_DEFINE_UNQUOTED(SLURM_API_MAJOR,    $SLURM_API_MAJOR,    [API current major])
 AC_DEFINE_UNQUOTED(SLURM_API_AGE,      $SLURM_API_AGE,      [API current age])
+AC_DEFINE_UNQUOTED(SLURM_API_REVISION, $SLURM_API_REVISION, [API current rev])
 AC_SUBST(SLURM_API_VERSION)
 AC_SUBST(SLURM_API_CURRENT)
-AC_SUBST(SLURM_API_REVISION)
+AC_SUBST(SLURM_API_MAJOR)
 AC_SUBST(SLURM_API_AGE)
+AC_SUBST(SLURM_API_REVISION)
 
 # rpm make target needs Version in META, not major and minor version numbers
 VERSION="`perl -ne 'print,exit if s/^\s*VERSION:\s*(\S*).*/\1/i' $srcdir/META`"

src/api/Makefile.am

@@ -15,21 +15,31 @@ endif
 
 # libslurm version information : 
 #
-# Update this information before a public release only!
+# Update META file information before a public release only!
 # 
-# If library source code has changed at all increment rev
-# (current:rev:age) = (current:rev+1:age)
+# Note that libtool builds libslurm.so.<major>.<age>.<rev>
+# where major = API_MAJOR = (API_CURRENT - API_AGE)
+# and   age   = API_AGE
+# and   rev   = API_REVISION
 #
-# If any interfaces have been added,removed, or changed increment current
-#  and set rev = 0;
+# The following examples are based upon initial values of API_MAJOR = 6,
+# API_AGE = 4, API_REVISION = 6.
 #
-# If any interfaces have been added increment age
+# If any interfaces have been added: increment API_MAJOR, increment API_AGE,
+# and set API_REVISION = 0 (e.g. libslurm.so.2.4.6 -> libslurm.so.2.5.0)
 #
-# If any interfaces have been removed, set age = 0
+# If any interfaces have been removed: increment API_CURRENT, set API_AGE = 0, 
+# and set API_REVISION = 0 (e.g. libslurm.so.2.4.6 -> libslurm.so.7.0.0)
+#
+# If any interfaces have changed: increment API_CURRENT only
+# (e.g. libslurm.so.2.4.6 -> libslurm.so.3.4.6)
+#
+# If the interfaces have not changed, but underlying code has changed at all: 
+# increment API_REVISION only (e.g. libslurm.so.2.4.6 -> libslurm.so.2.4.7)
 #
 current = $(SLURM_API_CURRENT)
-rev     = $(SLURM_API_REVISION)
 age     = $(SLURM_API_AGE)
+rev     = $(SLURM_API_REVISION)
 
 lib_LTLIBRARIES = libslurm.la