github.com/choleraehyq/pid@v0.0.18/goid_go1.4.go (about) 1 // Copyright 2015 Peter Mattis. 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or 12 // implied. See the License for the specific language governing 13 // permissions and limitations under the License. See the AUTHORS file 14 // for names of contributors. 15 16 //go:build go1.4 && !go1.5 17 // +build go1.4,!go1.5 18 19 package goid 20 21 import "unsafe" 22 23 var pointerSize = unsafe.Sizeof(uintptr(0)) 24 25 // Backdoor access to runtimeĀ·getg(). 26 func getg() uintptr // in goid_go1.4.s 27 28 // Get returns the id of the current goroutine. 29 func Get() int64 { 30 // The goid is the 16th field in the G struct where each field is a 31 // pointer, uintptr or padded to that size. See runtime.h from the 32 // Go sources. I'm not aware of a cleaner way to determine the 33 // offset. 34 return *(*int64)(unsafe.Pointer(getg() + 16*pointerSize)) 35 }