// bsls_systemclocktype.h -*-C++-*- #ifndef INCLUDED_BSLS_SYSTEMCLOCKTYPE #define INCLUDED_BSLS_SYSTEMCLOCKTYPE #include <bsls_ident.h> BSLS_IDENT("$Id: $") //@PURPOSE: Enumerate the set of system clock types. // //@CLASSES: // bsls::SystemClockType: namespace for a clock type 'enum' // //@DESCRIPTION: This component provides a namespace for the 'enum' type // 'bsls::SystemClockType::Enum', which enumerates the set of system clock // types. A 'bsls::SystemClockType' is particularly important when providing // time-out values to synchronization methods where those time-outs must be // consistent in environments where the system clocks may be changed. // ///Enumerators ///----------- //.. // Name Description // ----------- ------------------------------------------------------------- // e_REALTIME System clock that returns the current wall time maintained by // the system, and which is affected by adjustments to the // system's clock (i.e., time values returned may jump // "forwards" and "backwards" as the current time-of-day is // changed on the system). // // e_MONOTONIC System clock that returns the elapsed time since some // unspecified starting point in the past. The returned values // are monotonically non-decreasing, and are generally not // affected by changes to the system time. //.. // ///Usage ///----- // This section illustrates intended use of this component. // ///Example 1: Basic Syntax ///- - - - - - - - - - - - // The following snippets of code provide a simple illustration of using // 'bsls::SystemClockType'. // // First, we create a variable 'value' of type 'bsls::SystemClockType::Enum' // and initialize it with the enumerator value // 'bsls::SystemClockType::e_MONOTONIC': //.. // bsls::SystemClockType::Enum value = bsls::SystemClockType::e_MONOTONIC; //.. // Now, we store the address of its ASCII representation in a pointer variable, // 'asciiValue', of type 'const char *': //.. // const char *asciiValue = bsls::SystemClockType::toAscii(value); //.. // Finally, we verify the value of 'asciiValue': //.. // assert(0 == strcmp(asciiValue, "MONOTONIC")); //.. namespace BloombergLP { namespace bsls { // ====================== // struct SystemClockType // ====================== struct SystemClockType { // This 'struct' provides a namespace for enumerating the set of system // clock type for use in distinguishing which system clock to use for // measuring time. See 'Enum' in the TYPES sub-section for details. public: // TYPES enum Enum { // Enumeration clock type values. e_REALTIME, // System clock that returns the current wall time // maintained by the system, and which is affected by // adjustments to the system's clock (i.e., time values // returned may jump "forwards" and "backwards" as the // current time-of-day is changed on the system). e_MONOTONIC // System clock that returns the elapsed time since some // unspecified starting point in the past. The returned // values are monotonically non-decreasing, and are // generally not affected by changes to the system time. }; public: static const char *toAscii(SystemClockType::Enum value); // Return the non-modifiable string representation corresponding to the // specified enumeration 'value', if it exists, and a unique (error) // string otherwise. The string representation of 'value' matches its // corresponding enumerator name with the "e_" prefix elided. For // example: //.. // bsl::cout << SystemClockType::toAscii(SystemClockType::e_REALTIME); //.. // will print the following on standard output: //.. // REALTIME //.. // Note that specifying a 'value' that does not match any of the // enumerators will result in a string representation that is distinct // from any of those corresponding to the enumerators, but is otherwise // unspecified. }; } // close package namespace } // close enterprise namespace #endif // ---------------------------------------------------------------------------- // Copyright 2014 Bloomberg Finance L.P. // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. // ----------------------------- END-OF-FILE ----------------------------------