select文の内部実装見つけました

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1. select文の内部実装見つけました GeekGig #1, AUG 11 2021 さき(H.Saki) @saki-engineer

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3. TFMFDUจͰ͸ɺதʹDBTFจΛॻ͘͜ͱͰॲཧͷ෼ذΛ࣮ݱ͍ͯ͠Δɻ Select statements select文 var i1, i2 int var ch1,

   ch2 chan int select { case i1 = <-ch1: print("received ", i1, " from c1∖n") case ch2 <- i2: print("sent ", i2, " to c2∖n") default: print("no communication∖n") } νϟωϧDI͔Βͷड৴͕Մೳͳͱ͖࣮ߦ νϟωϧDI΁ͷૹ৴͕Մೳͳͱ͖࣮ߦ ͍ͣΕͰ΋ͳ͍৔߹ʹ࣮ߦ EFGBVMU
   DBTF͕ͳ͚Ε͹ϒϩοΫ

4. runtime/select.go runtime/select.go ߦ໨ʹʮ͜ͷϑΝΠϧʹ͸TFMFDUจͷ࣮૷ؚ͕·Ε͍ͯ·͢ʯͱͷهࡌ͋Γ

5. runtime/select.go runtime/select.go TFMFDUจຊମͷهड़͸ɺ-ͷ GVOD TFMFDUHP ͰߦΘΕ͍ͯΔɻ // selectgo implements the

   select statement. func selectgo(cas0 *scase, order0 *uint16, pc0 *uintptr, nsends, nrecvs int, block bool) (int, bool) { // (略) // 400行くらいある }
6. None

7. ͪΐͬͱԿݴͬͯΔ͔Θ͔Μͳ͍

8. ͜Μͳͱ͖͸ίϝϯτʹண໨͠Α͏ʂ

9. Implementation of select statement select文の実装 ϒϩοΫ͠ͳͯ͘Α͍৔߹͔Β࣮૷͍ͯ͠Δ͜ͱ͕֬ೝͰ͖Δɻ TFMFDU͢Δର৅ͷத͔Βૹड৴Ͱ͖Δ νϟωϧ͕ͳ͍͔Λ୳͍ͯ͠ΔͬΆ͍ l νϟωϧ͔Βड৴ՄˠSFDW

   l όοϑΝ͔Βड৴ՄˠCVGSFDW l νϟωϧDMPTFࡁΈˠSDMPTF ͔ͳʁͱ͍͏Ծઆ͕༰қʹཱͭ

10. Implementation of select statement select文の実装 ͦͷ࣍ʹɺϒϩοΫʹೖΔ৔߹ͷॲཧΛॻ͍͍ͯΔɻ ૹड৴Ͱ͖Δνϟωϧ͕ͳ ͔ͬͨͱ͖ͷॲཧ͔ͳʁ HPQBSLؔ਺ͰҎԼͷॲཧΛ࣮ߦ͠ɺTFMFDUจͷCMPDLΛ࣮ݱ 

    TFMFDUจΛ࣮ߦ͍ͯ͠Δΰʔϧʔνϯͷঢ়ଶΛSVOOJOH͔ΒXBJUJOHʹมߋ  ֘౰ΰʔϧʔνϯΛεϨου͔ΒҰ୴੾Γ཭͢

11. Summary まとめ l TFMFDUจຊମͷ࣮૷͸SVOUJNFTFMFDUHPͷதͷTFMFDUHPؔ਺ ◦ େମͷ(Pͷجװػೳ͸SVOUJNFύοέʔδͷதʹ͋Δ l ίʔυΛૉ௚ʹಡΈղ͔ͳͯ͘΋ɺ࣮૷ͷେ࿮Λ୳Δ͜ͱ͸Ͱ͖Δ ख͕͔ΓʹͳΔͷ͸ҎԼ ◦

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