Initial code.

src/lib/util/warn.c

Index: src/lib/util/warn.c
diff --git a/src/lib/util/warn.c b/src/lib/util/warn.c
new file mode 100644
index 0000000000000000000000000000000000000000..504f935b05eff9ccb0cf23696c418ba5a282df4b
--- /dev/null
+++ b/src/lib/util/warn.c
@@ -0,0 +1,75 @@
+/*-
+ * Copyright 2009 Colin Percival
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * This file was originally written by Colin Percival as part of the Tarsnap
+ * online backup system.
+ */
+#include "scrypt_platform.h"
+
+#ifdef HAVE_ERR_H
+/*
+ * Everything is provided through err.h and the associated library, so we
+ * don't need to do anything here.
+ */
+#else
+#include <errno.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "warn.h"
+
+const char * warn_progname = "(null)";
+
+void
+warn(const char * fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	fprintf(stderr, "%s", warn_progname);
+	if (fmt != NULL) {
+		fprintf(stderr, ": ");
+		vfprintf(stderr, fmt, ap);
+	}
+	fprintf(stderr, ": %s\n", strerror(errno));
+	va_end(ap);
+}
+
+void
+warnx(const char * fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	fprintf(stderr, "%s", warn_progname);
+	if (fmt != NULL) {
+		fprintf(stderr, ": ");
+		vfprintf(stderr, fmt, ap);
+	}
+	fprintf(stderr, "\n");
+	va_end(ap);
+}
+#endif