From e3b8203187235dc4add8cbc08c220eac049fbffd Mon Sep 17 00:00:00 2001
From: ridiculousfish <corydoras@ridiculousfish.com>
Date: Sun, 8 Dec 2019 14:43:30 -0800
Subject: [PATCH] Implement logger_t::log_fmt for narrow chars by trampolining
 to wide chars

This satifies the glibc.
---
 src/flog.cpp | 23 +++++++++++++++++++----
 1 file changed, 19 insertions(+), 4 deletions(-)

diff --git a/src/flog.cpp b/src/flog.cpp
index f46f22f2a..477a295dd 100644
--- a/src/flog.cpp
+++ b/src/flog.cpp
@@ -56,13 +56,28 @@ void logger_t::log_fmt(const category_t &cat, const wchar_t *fmt, ...) {
 }
 
 void logger_t::log_fmt(const category_t &cat, const char *fmt, ...) {
+    // glibc dislikes mixing wide and narrow output functions.
+    // So construct a narrow string in-place and output that via wide functions.
     va_list va;
     va_start(va, fmt);
-    log1(cat.name);
-    log1(": ");
-    std::vfprintf(file_, fmt, va);
-    log1('\n');
+    int ret = vsnprintf(nullptr, 0, fmt, va);
     va_end(va);
+
+    if (ret < 0) {
+        perror("vsnprintf");
+        return;
+    }
+    size_t len = static_cast<size_t>(ret) + 1;
+    std::unique_ptr<char[]> buff(new char[len]);
+
+    va_start(va, fmt);
+    ret = vsnprintf(buff.get(), len, fmt, va);
+    va_end(va);
+    if (ret < 0) {
+        perror("vsnprintf");
+        return;
+    }
+    log_fmt(cat, L"%s", buff.get());
 }
 
 }  // namespace flog_details