always add memory streams to stdio open file list

per interpretation for austin group issue #626, fflush(0) and exit()
must block waiting for a lock if another thread has locked a memory
stream with flockfile. this adds some otherwise-unnecessary
synchronization cost to use of memory streams, but there was already a
synchronization cost calling malloc anyway.

previously the stream was only added to the open file list in
single-threaded programs, so that upon subsequent call to
pthread_create, locking could be turned on for the stream.

1 files changed, 7 insertions, 6 deletions

diff --git a/src/stdio/open_memstream.c b/src/stdio/open_memstream.c
index c7330abe..9eafdfba 100644
--- a/src/stdio/open_memstream.c
+++ b/src/stdio/open_memstream.c
@@ -77,12 +77,13 @@ FILE *open_memstream(char **bufp, size_t *sizep)
 	f->seek = ms_seek;
 	f->close = ms_close;
 
-	if (!libc.threaded) {
-		f->lock = -1;
-		f->next = libc.ofl_head;
-		if (libc.ofl_head) libc.ofl_head->prev = f;
-		libc.ofl_head = f;
-	}
+	if (!libc.threaded) f->lock = -1;
+
+	OFLLOCK();
+	f->next = libc.ofl_head;
+	if (libc.ofl_head) libc.ofl_head->prev = f;
+	libc.ofl_head = f;
+	OFLUNLOCK();
 
 	return f;
 }