Add warning for fflush of closed write end on 2-way pipe.

6 files changed, 16 insertions, 2 deletions

diff --git a/ChangeLog b/ChangeLog
index 7ba50e8c..d34c136e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2016-04-04         Arnold D. Robbins     <arnold@skeeve.com>
+
+	* builtin.c (do_fflush): Add warning for flush to two-way
+	pipe where write end was closed.
+	* io.c (flush_io): Add some braces for the for loop.
+
 2016-04-02         Arnold D. Robbins     <arnold@skeeve.com>
 
 	* builtin.c (do_printf): If the redirection is two way but the
diff --git a/builtin.c b/builtin.c
index c4d3d3a1..a1c09d5a 100644
--- a/builtin.c
+++ b/builtin.c
@@ -237,6 +237,9 @@ do_fflush(int nargs)
 		fp = rp->output.fp;
 		if (fp != NULL)
 			status = rp->output.gawk_fflush(fp, rp->output.opaque);
+		else if ((rp->flag & RED_TWOWAY) != 0)
+				warning(_("fflush: cannot flush: two-way pipe `%s' has closed write end"),
+					file);
 	} else if ((fp = stdfile(tmp->stptr, tmp->stlen)) != NULL) {
 		status = fflush(fp);
 	} else {
diff --git a/io.c b/io.c
index de753973..fe1261aa 100644
--- a/io.c
+++ b/io.c
@@ -1328,7 +1328,7 @@ flush_io()
 			warning(_("error writing standard error (%s)"), strerror(errno));
 		status++;
 	}
-	for (rp = red_head; rp != NULL; rp = rp->next)
+	for (rp = red_head; rp != NULL; rp = rp->next) {
 		/* flush both files and pipes, what the heck */
 		if ((rp->flag & RED_WRITE) != 0 && rp->output.fp != NULL) {
 			if (rp->output.gawk_fflush(rp->output.fp, rp->output.opaque)) {
@@ -1344,6 +1344,7 @@ flush_io()
 				status++;
 			}
 		}
+	}
 	if (status != 0)
 		status = -1;	/* canonicalize it */
 	return status;
diff --git a/test/ChangeLog b/test/ChangeLog
index 80b2c233..2867f6cb 100644
--- a/test/ChangeLog
+++ b/test/ChangeLog
@@ -5,6 +5,8 @@
 	* clos1way2.awk, clos1way2.in, clos1way2.ok, clos1way3.awk,
 	clos1way3.ok, clos1way4.awk, clos1way4.ok, clos1way5.awk,
 	clos1way5.ok: New files.
+	* clos1way2.awk: Add call to fflush() to test it too.
+	* clos1way2.ok: Updated after code change.
 
 2016-02-18         Arnold D. Robbins     <arnold@skeeve.com>
 
diff --git a/test/clos1way2.awk b/test/clos1way2.awk
index 7dab6a67..5794bec5 100644
--- a/test/clos1way2.awk
+++ b/test/clos1way2.awk
@@ -1,5 +1,6 @@
 {
 	cmd = "cat - 1>&2; sleep 2"
 	print |& cmd; close(cmd, "to")
+	fflush(cmd)
 	print |& cmd; print ERRNO
 }
diff --git a/test/clos1way2.ok b/test/clos1way2.ok
index 22bd3e17..063c4213 100644
--- a/test/clos1way2.ok
+++ b/test/clos1way2.ok
@@ -1,3 +1,4 @@
-gawk: clos1way2.awk:4: (FILENAME=- FNR=1) fatal: print: attempt to write to closed write end of two-way pipe
+gawk: clos1way2.awk:4: (FILENAME=- FNR=1) warning: fflush: cannot flush: two-way pipe `cat - 1>&2; sleep 2' has closed write end
+gawk: clos1way2.awk:5: (FILENAME=- FNR=1) fatal: print: attempt to write to closed write end of two-way pipe
 test
 CODE: 2