背景
在AOSP里面，我们有时需要单独编译一个模块，用来查看这个模块是否能编译出来，编译出来的文件去了哪里。。。特别是AOSP源码有相关内容，例如libcups；但是在整个系统编译之后，生成的img烧录到板子中，检测却没有发现相关内容。这个时候就需要单独将其拎出来看看，这就需要到单独编译指令mm
mm指令使用步骤
1，加载环境变量
在根目录，source build/envsetup.sh
2，选择目标设备
lunch <device>
3，进入到目标文件夹内，进行编译
再cd到你需要单独编译的路径里面，直接mm
如果没有1，2步骤的前提下，直接使用mm指令，会出现指令没发现的情况。提示你去安装
apt install multimail
这个时候，不要去安装这个。这个多用户邮件一般情况下我们都用不到的
libcups的编译
下载cups包，下载OpenPrinting的
GitHub - OpenPrinting/cups: OpenPrinting CUPS Sources
解压后，将下面的Android.bp放到根目录；
libcups的Android.bp
// Copyright (C) 2016 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// *** THIS PACKAGE HAS SPECIAL LICENSING CONDITIONS. PLEASE
// CONSULT THE OWNERS AND opensource-licensing@google.com BEFORE
// DEPENDING ON IT IN YOUR PROJECT. ***
package {
default_applicable_licenses: ["external_libcups_license"],
}
// Added automatically by a large-scale-change that took the approach of
// 'apply every license found to every target'. While this makes sure we respect
// every license restriction, it may not be entirely correct.
//
// e.g. GPL in an MIT project might only apply to the contrib/ directory.
//
// Please consider splitting the single license below into multiple licenses,
// taking care not to lose any license_kind information, and overriding the
// default license using the 'licenses: [...]' property on targets as needed.
//
// For unused files, consider creating a 'fileGroup' with "//visibility:private"
// to attach the license to, and including a comment whether the files may be
// used in the current project.
//
// large-scale-change included anything that looked like it might be a license
// text as a license_text. e.g. LICENSE, NOTICE, COPYING etc.
//
// Please consider removing redundant or irrelevant files from 'license_text:'.
// See: http://go/android-license-faq
license {
name: "external_libcups_license",
visibility: [":__subpackages__"],
license_kinds: [
"SPDX-license-identifier-Apache-2.0",
"SPDX-license-identifier-BSD",
"SPDX-license-identifier-GPL",
"SPDX-license-identifier-GPL-2.0",
"SPDX-license-identifier-ISC",
"SPDX-license-identifier-LGPL",
"SPDX-license-identifier-MIT",
"SPDX-license-identifier-Zlib",
"legacy_by_exception_only", // by exception only
],
license_text: [
"LICENSE",
"NOTICE",
],
}
cc_library_shared {
name: "libcups",
sdk_version: "current",
srcs: [
"cups/array.c",
"cups/auth.c",
"cups/backchannel.c",
"cups/debug.c",
"cups/dest.c",
"cups/dest-job.c",
"cups/dest-localization.c",
"cups/dest-options.c",
"cups/dir.c",
"cups/encode.c",
"cups/file.c",
"cups/getdevices.c",
"cups/getputfile.c",
"cups/globals.c",
"cups/hash.c",
"cups/http.c",
"cups/http-addr.c",
"cups/http-addrlist.c",
"cups/http-support.c",
"cups/ipp.c",
"cups/ipp-support.c",
"cups/langprintf.c",
"cups/language.c",
"cups/md5.c",
"cups/md5passwd.c",
"cups/notify.c",
"cups/options.c",
"cups/pwg-media.c",
"cups/raster-error.c",
"cups/raster-stream.c",
"cups/raster-stubs.c",
"cups/request.c",
"cups/sidechannel.c",
"cups/snmp.c",
"cups/string.c",
"cups/tempfile.c",
"cups/thread.c",
"cups/tls-boringssl.c",
"cups/transcode.c",
"cups/usersys.c",
"cups/util.c",
],
cflags: [
"-D_PPD_DEPRECATED=",
"-Wextra",
"-Wall",
"-Wno-unused-parameter",
"-Wno-unused-function",
"-Wno-unused-variable",
"-Wno-unused-value",
"-Wno-sign-compare",
"-Wno-missing-field-initializers",
"-Wno-implicit-function-declaration",
"-Wno-deprecated-declarations",
"-Werror",
],
export_include_dirs: [
"cups",
"filter",
"."
],
arch: {
arm: {
instruction_set: "arm",
},
},
shared_libs: [
"libz",
"liblog",
"libcrypto",
"libssl",
],
}单独编译后，如果没出现问题的话，会在最后出现以下的路径
out/target/product/apollo-p2/obj/SHARED_LIBRARIES/libcups
androidexternal目录下新增一个可执行应用及编译_android external下新增编译一个lib库-CSDN博客