Fix for ticket:236, parallel makes are indeterminate.

[debian/gnuradio] / gnuradio-core / src / lib / gengen / Makefile.am

diff --git a/gnuradio-core/src/lib/gengen/Makefile.am b/gnuradio-core/src/lib/gengen/Makefile.am
index b1a3b261314bbb02ad99e037e9dcf463fa254097..a4330f10347e9335348e36e6e084375db765ad56 100644 (file)
--- a/gnuradio-core/src/lib/gengen/Makefile.am
+++ b/gnuradio-core/src/lib/gengen/Makefile.am
@@ -113,9 +113,35 @@ CODE_GENERATOR =                   \
 
 include $(srcdir)/Makefile.gen
 
-$(srcdir)/Makefile.gen $(GENERATED_H) $(GENERATED_I) $(GENERATED_CC): $(CODE_GENERATOR)
+# Ensure parallel does the right thing.
+# http://sources.redhat.com/automake/automake.html#Multiple-Outputs
+
+generate-stamp: $(CODE_GENERATOR)
+       @rm -f generate-tmp
+       @touch generate-tmp
        PYTHONPATH=$(top_srcdir)/gnuradio-core/src/python srcdir=$(srcdir) $(PYTHON) $(srcdir)/generate_all.py
        touch $(srcdir)/Makefile.in
+       @mv -f generate-tmp $@
+
+
+$(srcdir)/Makefile.gen $(GENERATED_H) $(GENERATED_I) $(GENERATED_CC): generate-stamp
+## Recover from the removal of $@
+       @if test -f $@; then :; else \
+               trap 'rm -rf generate-lock generate-stamp' 1 2 13 15; \
+               if mkdir generate-lock 2>/dev/null; then \
+## This code is being executed by the first process.
+                 rm -f generate-stamp; \
+                 $(MAKE) $(AM_MAKEFLAGS) generate-stamp; \
+                 rmdir generate-lock; \
+               else \
+## This code is being executed by the follower processes.
+## Wait until the first process is done.
+                 while test -d generate-lock; do sleep 1; done; \
+## Succeed if and only if the first process succeeded.
+                 test -f generate-stamp; exit $$?; \
+               fi; \
+             fi
+
 
 BUILT_SOURCES = $(GENERATED_H) $(GENERATED_I) $(GENERATED_CC)