diff --git a/src/mux_fcgi.c b/src/mux_fcgi.c
index d2d2dd4..c502670 100644
--- a/src/mux_fcgi.c
+++ b/src/mux_fcgi.c
@@ -440,7 +440,7 @@
 
 	/* Display the value to the 4th argument (level > STATE) */
 	if (src->level > TRACE_LEVEL_STATE && val)
-		chunk_appendf(&trace_buf, " - VAL=%lu", *val);
+		chunk_appendf(&trace_buf, " - VAL=%lu", (long)*val);
 
 	/* Display status-line if possible (verbosity > MINIMAL) */
 	if (src->verbosity > FCGI_VERB_MINIMAL && htx && htx_nbblks(htx)) {
diff --git a/src/mux_h1.c b/src/mux_h1.c
index b548849..d7e35cd 100644
--- a/src/mux_h1.c
+++ b/src/mux_h1.c
@@ -287,7 +287,7 @@
 
 	/* Display the value to the 4th argument (level > STATE) */
 	if (src->level > TRACE_LEVEL_STATE && val)
-		chunk_appendf(&trace_buf, " - VAL=%lu", *val);
+		chunk_appendf(&trace_buf, " - VAL=%lu", (long)*val);
 
 	/* Display status-line if possible (verbosity > MINIMAL) */
 	if (src->verbosity > H1_VERB_MINIMAL && htx && htx_nbblks(htx)) {
diff --git a/src/stream.c b/src/stream.c
index 2c0d2c8..4efc16b 100644
--- a/src/stream.c
+++ b/src/stream.c
@@ -225,10 +225,10 @@
 	else {
 		chunk_appendf(&trace_buf, " req=(%p .fl=0x%08x .ana=0x%08x .exp(r,w,a)=(%u,%u,%u) .o=%lu .tot=%llu .to_fwd=%u)",
 			      req, req->flags, req->analysers, req->rex, req->wex, req->analyse_exp,
-			      req->output, req->total, req->to_forward);
+			      (long)req->output, req->total, req->to_forward);
 		chunk_appendf(&trace_buf, " res=(%p .fl=0x%08x .ana=0x%08x .exp(r,w,a)=(%u,%u,%u) .o=%lu .tot=%llu .to_fwd=%u)",
 			      res, res->flags, res->analysers, res->rex, res->wex, res->analyse_exp,
-			      res->output, res->total, res->to_forward);
+			      (long)res->output, res->total, res->to_forward);
 	}
 
 	if (src->verbosity == STRM_VERB_SIMPLE ||