From 23a9df0f30a314853f05148f8feb6664323f0331 Mon Sep 17 00:00:00 2001
From: Consolatis <35009135+Consolatis@users.noreply.github.com>
Date: Fri, 23 Aug 2024 20:09:47 +0200
Subject: [PATCH] common/buf.c: use 0 directly in vsnprintf()

This works around a wrong truncation warning in older GCC versions:
```
../src/common/buf.c:110:10: error: null destination pointer [-Werror=format-truncation=]
  110 |  int n = vsnprintf(NULL, size, fmt, ap)
```
---
 src/common/buf.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/src/common/buf.c b/src/common/buf.c
index d36f64d5..70be9ed0 100644
--- a/src/common/buf.c
+++ b/src/common/buf.c
@@ -103,18 +103,17 @@ buf_add_fmt(struct buf *s, const char *fmt, ...)
 	if (string_null_or_empty(fmt)) {
 		return;
 	}
-	size_t size = 0;
 	va_list ap;
 
 	va_start(ap, fmt);
-	int n = vsnprintf(NULL, size, fmt, ap);
+	int n = vsnprintf(NULL, 0, fmt, ap);
 	va_end(ap);
 
 	if (n < 0) {
 		return;
 	}
 
-	size = (size_t)n + 1;
+	size_t size = (size_t)n + 1;
 	buf_expand(s, s->len + size);
 
 	va_start(ap, fmt);