1 files changed, 80 insertions, 0 deletions

diff --git a/Documentation/perf_counter/usage.c b/Documentation/perf_counter/usage.c
new file mode 100644
index 000000000000..7a10421fe6b4
--- /dev/null
+++ b/Documentation/perf_counter/usage.c
@@ -0,0 +1,80 @@
+/*
+ * GIT - The information manager from hell
+ *
+ * Copyright (C) Linus Torvalds, 2005
+ */
+#include "util.h"
+
+static void report(const char *prefix, const char *err, va_list params)
+{
+        char msg[1024];
+        vsnprintf(msg, sizeof(msg), err, params);
+        fprintf(stderr, "%s%s\n", prefix, msg);
+}
+
+static NORETURN void usage_builtin(const char *err)
+{
+        fprintf(stderr, "usage: %s\n", err);
+        exit(129);
+}
+
+static NORETURN void die_builtin(const char *err, va_list params)
+{
+        report("fatal: ", err, params);
+        exit(128);
+}
+
+static void error_builtin(const char *err, va_list params)
+{
+        report("error: ", err, params);
+}
+
+static void warn_builtin(const char *warn, va_list params)
+{
+        report("warning: ", warn, params);
+}
+
+/* If we are in a dlopen()ed .so write to a global variable would segfault
+ * (ugh), so keep things static. */
+static void (*usage_routine)(const char *err) NORETURN = usage_builtin;
+static void (*die_routine)(const char *err, va_list params) NORETURN = die_builtin;
+static void (*error_routine)(const char *err, va_list params) = error_builtin;
+static void (*warn_routine)(const char *err, va_list params) = warn_builtin;
+
+void set_die_routine(void (*routine)(const char *err, va_list params) NORETURN)
+{
+        die_routine = routine;
+}
+
+void usage(const char *err)
+{
+        usage_routine(err);
+}
+
+void die(const char *err, ...)
+{
+        va_list params;
+
+        va_start(params, err);
+        die_routine(err, params);
+        va_end(params);
+}
+
+int error(const char *err, ...)
+{
+        va_list params;
+
+        va_start(params, err);
+        error_routine(err, params);
+        va_end(params);
+        return -1;
+}
+
+void warning(const char *warn, ...)
+{
+        va_list params;
+
+        va_start(params, warn);
+        warn_routine(warn, params);
+        va_end(params);
+}