1 //
2 //  Copyright 2019 The Abseil Authors.
3 //
4 // Licensed under the Apache License, Version 2.0 (the "License");
5 // you may not use this file except in compliance with the License.
6 // You may obtain a copy of the License at
7 //
8 //      https://www.apache.org/licenses/LICENSE-2.0
9 //
10 // Unless required by applicable law or agreed to in writing, software
11 // distributed under the License is distributed on an "AS IS" BASIS,
12 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 // See the License for the specific language governing permissions and
14 // limitations under the License.
15 
16 #ifndef ABSL_FLAGS_USAGE_H_
17 #define ABSL_FLAGS_USAGE_H_
18 
19 #include "absl/base/config.h"
20 #include "absl/strings/string_view.h"
21 
22 // --------------------------------------------------------------------
23 // Usage reporting interfaces
24 
25 namespace absl {
26 ABSL_NAMESPACE_BEGIN
27 
28 // Sets the "usage" message to be used by help reporting routines.
29 // For example:
30 //  absl::SetProgramUsageMessage(
31 //      absl::StrCat("This program does nothing.  Sample usage:\n", argv[0],
32 //                   " <uselessarg1> <uselessarg2>"));
33 // Do not include commandline flags in the usage: we do that for you!
34 // Note: Calling SetProgramUsageMessage twice will trigger a call to std::exit.
35 void SetProgramUsageMessage(absl::string_view new_usage_message);
36 
37 // Returns the usage message set by SetProgramUsageMessage().
38 absl::string_view ProgramUsageMessage();
39 
40 ABSL_NAMESPACE_END
41 }  // namespace absl
42 
43 #endif  // ABSL_FLAGS_USAGE_H_
44