absl/flags/usage.h

0001 //
0002 //  Copyright 2019 The Abseil Authors.
0003 //
0004 // Licensed under the Apache License, Version 2.0 (the "License");
0005 // you may not use this file except in compliance with the License.
0006 // You may obtain a copy of the License at
0007 //
0008 //      https://www.apache.org/licenses/LICENSE-2.0
0009 //
0010 // Unless required by applicable law or agreed to in writing, software
0011 // distributed under the License is distributed on an "AS IS" BASIS,
0012 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
0013 // See the License for the specific language governing permissions and
0014 // limitations under the License.
0015
0016 #ifndef ABSL_FLAGS_USAGE_H_
0017 #define ABSL_FLAGS_USAGE_H_
0018
0019 #include "absl/base/config.h"
0020 #include "absl/strings/string_view.h"
0021
0022 // --------------------------------------------------------------------
0023 // Usage reporting interfaces
0024
0025 namespace absl {
0026 ABSL_NAMESPACE_BEGIN
0027
0028 // Sets the "usage" message to be used by help reporting routines.
0029 // For example:
0030 //  absl::SetProgramUsageMessage(
0031 //      absl::StrCat("This program does nothing.  Sample usage:\n", argv[0],
0032 //                   " <uselessarg1> <uselessarg2>"));
0033 // Do not include commandline flags in the usage: we do that for you!
0034 // Note: Calling SetProgramUsageMessage twice will trigger a call to std::exit.
0035 void SetProgramUsageMessage(absl::string_view new_usage_message);
0036
0037 // Returns the usage message set by SetProgramUsageMessage().
0038 absl::string_view ProgramUsageMessage();
0039
0040 ABSL_NAMESPACE_END
0041 }  // namespace absl
0042
0043 #endif  // ABSL_FLAGS_USAGE_H_