Note that AsyncSignalSafeWriteToStderr preserves errno, and inline one use of it into a lambda.

PiperOrigin-RevId: 535245982
Change-Id: I816f60c8b6476536df6836500f01c9a3ad88ddd4

absl/base/internal/raw_logging.h

@@ -129,7 +129,7 @@ void RawLog(absl::LogSeverity severity, const char* file, int line,
             const char* format, ...) ABSL_PRINTF_ATTRIBUTE(4, 5);
             const char* format, ...) ABSL_PRINTF_ATTRIBUTE(4, 5);
 
 
 // Writes the provided buffer directly to stderr, in a signal-safe, low-level
 // Writes the provided buffer directly to stderr, in a signal-safe, low-level
-// manner.
+// manner.  Preserves errno.
 void AsyncSignalSafeWriteToStderr(const char* s, size_t len);
 void AsyncSignalSafeWriteToStderr(const char* s, size_t len);
 
 
 // compile-time function to get the "base" filename, that is, the part of
 // compile-time function to get the "base" filename, that is, the part of

absl/debugging/failure_signal_handler.cc

@@ -236,10 +236,6 @@ static void InstallOneFailureHandler(FailureSignalData* data,
 
 
 #endif
 #endif
 
 
-static void WriteToStderr(const char* data) {
-  absl::raw_log_internal::AsyncSignalSafeWriteToStderr(data, strlen(data));
-}
-
 static void WriteSignalMessage(int signo, int cpu,
 static void WriteSignalMessage(int signo, int cpu,
                                void (*writerfn)(const char*)) {
                                void (*writerfn)(const char*)) {
   char buf[96];
   char buf[96];
@@ -380,7 +376,11 @@ static void AbslFailureSignalHandler(int signo, siginfo_t*, void* ucontext) {
 #endif
 #endif
 
 
   // First write to stderr.
   // First write to stderr.
-  WriteFailureInfo(signo, ucontext, my_cpu, WriteToStderr);
+  WriteFailureInfo(
+      signo, ucontext, my_cpu, +[](const char* data) {
+        absl::raw_log_internal::AsyncSignalSafeWriteToStderr(data,
+                                                             strlen(data));
+      });
 
 
   // Riskier code (because it is less likely to be async-signal-safe)
   // Riskier code (because it is less likely to be async-signal-safe)
   // goes after this point.
   // goes after this point.