github.com/code-reading/golang@v0.0.0-20220303082512-ba5bc0e589a3/go/src/net/main_conf_test.go (about)

     1  // Copyright 2015 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  //go:build !js && !plan9 && !windows
     6  // +build !js,!plan9,!windows
     7  
     8  package net
     9  
    10  // forceGoDNS forces the resolver configuration to use the pure Go resolver
    11  // and returns a fixup function to restore the old settings.
    12  func forceGoDNS() func() {
    13  	c := systemConf()
    14  	oldGo := c.netGo
    15  	oldCgo := c.netCgo
    16  	fixup := func() {
    17  		c.netGo = oldGo
    18  		c.netCgo = oldCgo
    19  	}
    20  	c.netGo = true
    21  	c.netCgo = false
    22  	return fixup
    23  }
    24  
    25  // forceCgoDNS forces the resolver configuration to use the cgo resolver
    26  // and returns a fixup function to restore the old settings.
    27  // (On non-Unix systems forceCgoDNS returns nil.)
    28  func forceCgoDNS() func() {
    29  	c := systemConf()
    30  	oldGo := c.netGo
    31  	oldCgo := c.netCgo
    32  	fixup := func() {
    33  		c.netGo = oldGo
    34  		c.netCgo = oldCgo
    35  	}
    36  	c.netGo = false
    37  	c.netCgo = true
    38  	return fixup
    39  }