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// 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.
//go:build aix || darwin || dragonfly || freebsd || (js && wasm) || linux || netbsd || openbsd || solaris || windows || plan9
// +build aix darwin dragonfly freebsd js,wasm linux netbsd openbsd solaris windows plan9
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.
// Called from syscall.Setenv.
//go:linkname syscall_setenv_c syscall.setenv_c
func syscall_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.
// Called from syscall.unsetenv.
//go:linkname syscall_unsetenv_c syscall.unsetenv_c
func syscall_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])
}
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