2 // Copyright 2019 The Abseil Authors.
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
8 // https://www.apache.org/licenses/LICENSE-2.0
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.
16 #ifndef ABSL_FLAGS_INTERNAL_USAGE_H_
17 #define ABSL_FLAGS_INTERNAL_USAGE_H_
22 #include "absl/flags/declare.h"
23 #include "absl/flags/internal/commandlineflag.h"
24 #include "absl/strings/string_view.h"
26 // --------------------------------------------------------------------
27 // Usage reporting interfaces
30 namespace flags_internal {
32 // The format to report the help messages in.
33 enum class HelpFormat {
37 // Outputs the help message describing specific flag.
38 void FlagHelp(std::ostream& out, const flags_internal::CommandLineFlag& flag,
39 HelpFormat format = HelpFormat::kHumanReadable);
41 // Produces the help messages for all flags matching the filter. A flag matches
42 // the filter if it is defined in a file with a filename which includes
43 // filter string as a substring. You can use '/' and '.' to restrict the
44 // matching to a specific file names. For example:
45 // FlagsHelp(out, "/path/to/file.");
46 // restricts help to only flags which resides in files named like:
47 // .../path/to/file.<ext>
48 // for any extension 'ext'. If the filter is empty this function produces help
49 // messages for all flags.
50 void FlagsHelp(std::ostream& out, absl::string_view filter = {},
51 HelpFormat format = HelpFormat::kHumanReadable);
53 // --------------------------------------------------------------------
55 // If any of the 'usage' related command line flags (listed on the bottom of
56 // this file) has been set this routine produces corresponding help message in
57 // the specified output stream and returns:
58 // 0 - if "version" or "only_check_flags" flags were set and handled.
59 // 1 - if some other 'usage' related flag was set and handled.
60 // -1 - if no usage flags were set on a commmand line.
61 // Non negative return values are expected to be used as an exit code for a
63 int HandleUsageFlags(std::ostream& out);
65 } // namespace flags_internal
68 ABSL_DECLARE_FLAG(bool, help);
69 ABSL_DECLARE_FLAG(bool, helpfull);
70 ABSL_DECLARE_FLAG(bool, helpshort);
71 ABSL_DECLARE_FLAG(bool, helppackage);
72 ABSL_DECLARE_FLAG(bool, version);
73 ABSL_DECLARE_FLAG(bool, only_check_args);
74 ABSL_DECLARE_FLAG(std::string, helpon);
75 ABSL_DECLARE_FLAG(std::string, helpmatch);
77 #endif // ABSL_FLAGS_INTERNAL_USAGE_H_