// Copyright 2012 The Go Authors. All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. package runtime import "unsafe" func gogetenv(key string) string { env := environ() if env == nil { throw("getenv before env init") } for _, s := range env { if len(s) > len(key) && s[len(key)] == '=' && envKeyEqual(s[:len(key)], key) { return s[len(key)+1:] } } return "" } // envKeyEqual reports whether a == b, with ASCII-only case insensitivity // on Windows. The two strings must have the same length. func envKeyEqual(a, b string) bool { if GOOS == "windows" { // case insensitive for i := 0; i < len(a); i++ { ca, cb := a[i], b[i] if ca == cb || lowerASCII(ca) == lowerASCII(cb) { continue } return false } return true } return a == b } func lowerASCII(c byte) byte { if 'A' <= c && c <= 'Z' { return c + ('a' - 'A') } return c } var _cgo_setenv unsafe.Pointer // pointer to C function var _cgo_unsetenv unsafe.Pointer // pointer to C function // Update the C environment if cgo is loaded. func setenv_c(k string, v string) { if _cgo_setenv == nil { return } arg := [2]unsafe.Pointer{cstring(k), cstring(v)} asmcgocall(_cgo_setenv, unsafe.Pointer(&arg)) } // Update the C environment if cgo is loaded. func unsetenv_c(k string) { if _cgo_unsetenv == nil { return } arg := [1]unsafe.Pointer{cstring(k)} asmcgocall(_cgo_unsetenv, unsafe.Pointer(&arg)) } func cstring(s string) unsafe.Pointer { p := make([]byte, len(s)+1) copy(p, s) return unsafe.Pointer(&p[0]) }