From 8626da73b6596bdd30c1289525db59f09737226d Mon Sep 17 00:00:00 2001
From: Yann Collet <cyan@fb.com>
Date: Wed, 26 Mar 2025 19:21:48 -0700
Subject: [PATCH] add error message clarification for inputs as process
 substitution

---
 programs/fileio.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/programs/fileio.c b/programs/fileio.c
index 6514bf32c..6c6faa485 100644
--- a/programs/fileio.c
+++ b/programs/fileio.c
@@ -660,6 +660,9 @@ FIO_openDstFile(FIO_ctx_t* fCtx, FIO_prefs_t* const prefs,
 #endif
         if (f == NULL) {
             DISPLAYLEVEL(1, "zstd: %s: %s\n", dstFileName, strerror(errno));
+            if (UTIL_isFileDescriptorPipe(dstFileName)) {
+                DISPLAYLEVEL(1, "When using process substitution (<(...)), specify an output destination with -o or -c. \n");
+            }
         } else {
             /* An increased buffer size can provide a significant performance
              * boost on some platforms. Note that providing a NULL buf with a