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comparison foosdk/sdk/pfc/once.h @ 1:20d02a178406 default tip

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*: check in everything else yay
author Paper <paper@tflc.us>
date Mon, 05 Jan 2026 02:15:46 -0500
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0:e9bb126753e7 1:20d02a178406
1 #pragma once
2
3 #include <functional>
4 #include "event.h"
5 #include <memory>
6 #include "lockless.h"
7
8 #ifdef __ANDROID__
9 #define PFC_CUSTOM_ONCE_FLAG 1
10 #endif
11
12 #ifndef PFC_CUSTOM_ONCE_FLAG
13 #define PFC_CUSTOM_ONCE_FLAG 0
14 #endif
15
16 #if ! PFC_CUSTOM_ONCE_FLAG
17 #include <mutex>
18 #endif
19
20 namespace pfc {
21 #if PFC_CUSTOM_ONCE_FLAG
22 struct once_flag {
23 bool inProgress = false, done = false;
24 std::shared_ptr<::pfc::event> waitFor;
25 };
26
27 void call_once( once_flag &, std::function<void () > );
28 #else
29 using std::once_flag;
30 using std::call_once;
31 #endif
32
33 //! Minimalist class to call some function only once. \n
34 //! Presumes low probability of concurrent run() calls actually happening, \n
35 //! but frequent calls once already initialized, hence only using basic volatile bool check. \n
36 //! If using a modern compiler you might want to use std::call_once instead. \n
37 //! The called function is not expected to throw exceptions.
38 struct once_flag_lite {
39 threadSafeInt::val_t guard = 0;
40 volatile bool done = false;
41 };
42
43 void call_once( once_flag_lite &, std::function<void () > );
44
45 class runOnceLock {
46 public:
47 void run(std::function<void()> f) {call_once(m_flag, f);}
48 private:
49 once_flag_lite m_flag;
50 };
51 }