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<2012 12 15> C标准库&POSIX标准库及其移植

2012-12-15 14:15 453 查看
在LINUX程序设计当中，经常会遇到头文件包含的问题，那么这些头文件到底在哪个路径下？具体的头文件路径依赖于程序性质(应用程序还是和内核相关的程序？本地编译还是交叉编译？)和编译器，下面分别叙述。

机器环境如下：UBUNTU10.04LTS，自己另外安装的LINUX内核源码目录为/usr/src/kernel，交叉链接器arm-linux-gcc安装目录为/usr/lcoal/arm/2.95.3/
【1.如果是应用程序，并且使用GCC进行普通编译】，如果编译时没有使用-I选项指定包含目录的话，那么默认的头文件目录在/usr/include下，可以在shell下输入如下命令

echo 'main(){}'|gcc -E -v -


看到如下输出内容

Using built-in specs.
Target: i486-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu 4.4.3-4ubuntu5' --with-bugurl=file:///usr/share/doc/gcc-4.4/README.Bugs --enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr --enable-shared --enable-multiarch--enable-linker-build-id --with-system-zlib --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.4 --program-suffix=-4.4 --enable-nls --enable-clocale=gnu --enable-libstdcxx-debug--enable-plugin --enable-objc-gc --enable-targets=all --disable-werror --with-arch-32=i486 --with-tune=generic --enable-checking=release --build=i486-linux-gnu --host=i486-linux-gnu --target=i486-linux-gnu
Thread model: posix
gcc version 4.4.3 (Ubuntu 4.4.3-4ubuntu5)
COLLECT_GCC_OPTIONS='-E' '-v' '-mtune=generic' '-march=i486'
/usr/lib/gcc/i486-linux-gnu/4.4.3/cc1 -E -quiet -v - -D_FORTIFY_SOURCE=2 -mtune=generic -march=i486 -fstack-protector
ignoring nonexistent directory "/usr/local/include/i486-linux-gnu"
ignoring nonexistent directory "/usr/lib/gcc/i486-linux-gnu/4.4.3/http://www.cnblogs.com/http://www.cnblogs.com/i486-linux-gnu/include"
ignoring nonexistent directory "/usr/include/i486-linux-gnu"
#include "..." search starts here:
#include <...> search starts here:
/usr/local/include
/usr/lib/gcc/i486-linux-gnu/4.4.3/include
/usr/lib/gcc/i486-linux-gnu/4.4.3/include-fixed
/usr/include
End of search list.
# 1 "<stdin>"
# 1 "<built-in>"
# 1 "<command-line>"
# 1 "<stdin>"
main(){}
COMPILER_PATH=/usr/lib/gcc/i486-linux-gnu/4.4.3/:/usr/lib/gcc/i486-linux-gnu/4.4.3/:/usr/lib/gcc/i486-linux-gnu/:/usr/lib/gcc/i486-linux-gnu/4.4.3/:/usr/lib/gcc/i486-linux-gnu/:/usr/lib/gcc/i486-linux-gnu/4.4.3/:/usr/lib/gcc/i486-linux-gnu/
LIBRARY_PATH=/usr/lib/gcc/i486-linux-gnu/4.4.3/:/usr/lib/gcc/i486-linux-gnu/4.4.3/:/usr/lib/gcc/i486-linux-gnu/4.4.3/../../../../lib/:/lib/../lib/:/usr/lib/../lib/:/usr/lib/gcc/i486-linux-gnu/4.4.3/../../../:/lib/:/usr/lib/:/usr/lib/i486-linux-gnu/
COLLECT_GCC_OPTIONS='-E' '-v' '-mtune=generic' '-march=i486'


这就是内定的include文件搜索路径

#include "..." search starts here:
#include <...> search starts here:
/usr/local/include
/usr/lib/gcc/i486-linux-gnu/4.4.3/include
/usr/lib/gcc/i486-linux-gnu/4.4.3/include-fixed
/usr/include
End of search list.


实际上，这些内定的include文件搜索路径，是存放在specs文件中

【2.如果是应用程序，采用交叉编译】，编译时没有使用-I选项指定包含目录的话，那么默认的头文件搜索路径为/usr/local/arm/2.95.3/arm-linux/include，即交叉编译器的安装目录下的include目录，执行如下命令

echo 'main(){}'|arm-linux-gcc -E -v -


看到如下输出内容

Reading specs from /usr/local/arm/2.95.3/lib/gcc-lib/arm-linux/2.95.3/specs
gcc version 2.95.3 20010315 (release)
/usr/local/arm/2.95.3/lib/gcc-lib/arm-linux/2.95.3/cpp0 -lang-c -v -D__GNUC__=2-D__GNUC_MINOR__=95 -Dunix -D__arm__ -Dlinux -D__ELF__ -D__unix__ -D__arm__ -D__linux__-D__ELF__ -D__unix -D__linux -Asystem(unix) -Asystem(posix) -Acpu(arm) -Amachine(arm)-D__CHAR_UNSIGNED__ -D__ARM_ARCH_3__ -D__APCS_32__ -
GNU CPP version 2.95.3 20010315 (release) (ARM GNU/Linux with ELF)
#include "..." search starts here:
#include <...> search starts here:
/usr/local/arm/2.95.3/lib/gcc-lib/arm-linux/2.95.3/include
/usr/local/arm/2.95.3/lib/gcc-lib/arm-linux/2.95.3/../../../../arm-linux/sys-include
/usr/local/arm/2.95.3/lib/gcc-lib/arm-linux/2.95.3/../../../../arm-linux/include
End of search list.
The following default directories have been omitted from the search path:
/usr/local/arm/2.95.3/lib/gcc-lib/arm-linux/2.95.3/../../../../include/g++-3
End of omitted list.
# 1 ""
main(){}


这就是内定的include文件搜索路径

#include "..." search starts here:
#include <...> search starts here:
/usr/local/arm/2.95.3/lib/gcc-lib/arm-linux/2.95.3/include
/usr/local/arm/2.95.3/lib/gcc-lib/arm-linux/2.95.3/../../../../arm-linux/sys-include
/usr/local/arm/2.95.3/lib/gcc-lib/arm-linux/2.95.3/../../../../arm-linux/include
End of search list.


即在采用交叉编译时，应用程序所包含的头文件是在交叉编译器的安装目录下。

【3.如果是和内核相关的程序】,比如驱动程序，那么所包含的头文件是在内核源码的安装目录下，即/usr/src/kernel/include，这时一般要在Makefile文件中指定内核源码目录，在编译时指定INCLUDE目录，可参考“[b]http://blogold.chinaunix.net/u3/119151/showart_2342316.html文章中Makefile文件内容[/b]

[b][b]【4.总结】：[/b][/b]
[b][b]nclude的header文件,连结数据库，系统定义，总共有下列来源指定编译器去那找。
当初在编译时指定的(在~gcc/gcc/collect2.c:locatelib() ，写在specs内的
后来用-D -I -L指定的
gcc环境变量设定(编译的时候)
ld.so的环境变量(这是run time的时候）[/b][/b]

========================================================================

在 C语言程序设计里，C 标准函数库（C Standard library）收集所有目前符合标准的头文件（head file），以及常用的函数库实现程序，例如 I/O 输入输出和字符串控制。1995年，Normative Addendum 1 (NA1)批准了三个头文件(iso646.h, wchar.h, and wctype.h)增加到C标准函数库中。C99标准增加了六个头文件(complex.h, fenv.h, inttypes.h, stdbool.h, stdint.h, and tgmath.h)。C11标准中又新增了5个头文件(stdalign.h, stdatomic.h, stdnoreturn.h, threads.h, and uchar.h)。至此，C标准函数库共29个头文件：

名字源自描述
<assert.h>
Contains the assert macro, used to assist with detecting logical errors and other types of bug in debugging versions of a program.
<complex.h>
C99A set of functions for manipulating 复数.
<ctype.h>
Defines set of functions used to classify characters by their types or to convert between upper and lower case in a way that is independent of the used character set (typically ASCII or one of its extensions, although implementations utilizing EBCDIC are also known).
<errno.h>
For testing error codes reported by library functions.
<fenv.h>
C99Defines a set of functions for controlling 浮点数 environment.
<float.h>
Defines macro constants specifying the implementation-specific properties of the 浮点数 library.
<inttypes.h>
C99Defines exact width integer types.
<iso646.h>
NA1Defines several macros that are equivalent to some of the operators in C. For programming in ISO 646 variant character sets.
<limits.h>
Defines macro constants specifying the implementation-specific properties of the integer types.
<locale.h>
Defines C localization functions.
<math.h>
Defines C mathematical functions.
<setjmp.h>
Declares the macros 
setjmp
and 
longjmp
, which are used for non-local exits.
<signal.h>
Defines C signal handling functions.
<stdalign.h>
C11For querying and specifying the data structure alignment of objects.
<stdarg.h>
For accessing a varying number of arguments passed to functions.
<stdatomic.h>
C11For atomic operations on data shared between threads.
<stdbool.h>
C99Defines a boolean data type.
<stddef.h>
Defines several useful types and macros.
<stdint.h>
C99Defines exact width integer types.
<stdio.h>
Defines core input and output functions
<stdlib.h>
Defines numeric conversion functions, pseudo-random numbers generation functions, dynamicmemory allocation, process control functions
<stdnoreturn.h>
C11For specifying non-returning functions.
<string.h>
Defines C string handling functions.
<tgmath.h>
C99Defines type-generic mathematical functions.
<threads.h>
C11Defines functions for managing multiple threads as well as mutexes and condition variables.
Defines date and time handling functions
<uchar.h>
C11Types and functions for manipulating Unicode characters.
<wchar.h>
NA1Defines wide string handling functions.
<wctype.h>
NA1Defines set of functions used to classify wide characters by their types or to convert between upper and lower case
============================================================

POSIX标准定义的头文件<dirent.h> 目录项<fcntl.h> 文件控制<fnmatch.h> 文件名匹配类型<glob.h> 路径名模式匹配类型<grp.h> 组文件<netdb.h> 网络数据库操作<pwd.h> 口令文件<regex.h> 正则表达式<tar.h> TAR归档值<termios.h> 终端I/O<unistd.h> 符号常量<utime.h> 文件时间<wordexp.h> 字符扩展类型-------------------------<arpa/inet.h> INTERNET定义<net/if.h> 套接字本地接口<netinet/in.h> INTERNET地址族<netinet/tcp.h> 传输控制协议定义------------------------- <sys/mman.h> 内存管理声明<sys/select.h> Select函数<sys/socket.h> 套接字借口<sys/stat.h> 文件状态<sys/times.h> 进程时间<sys/types.h> 基本系统数据类型<sys/un.h> UNIX域套接字定义<sys/utsname.h> 系统名<sys/wait.h> 进程控制 ------------------------------POSIX定义的XSI扩展头文件<cpio.h> cpio归档值 <dlfcn.h> 动态链接<fmtmsg.h> 消息显示结构<ftw.h> 文件树漫游<iconv.h> 代码集转换使用程序<langinfo.h> 语言信息常量<libgen.h> 模式匹配函数定义<monetary.h> 货币类型<ndbm.h> 数据库操作<nl_types.h> 消息类别<poll.h> 轮询函数<search.h> 搜索表<strings.h> 字符串操作<syslog.h> 系统出错日志记录<ucontext.h> 用户上下文<ulimit.h> 用户限制<utmpx.h> 用户帐户数据库 -----------------------------<sys/ipc.h> IPC(命名管道)<sys/msg.h> 消息队列<sys/resource.h>资源操作<sys/sem.h> 信号量<sys/shm.h> 共享存储<sys/statvfs.h> 文件系统信息<sys/time.h> 时间类型<sys/timeb.h> 附加的日期和时间定义<sys/uio.h> 矢量I/O操作 ------------------------------POSIX定义的可选头文件<aio.h> 异步I/O<mqueue.h> 消息队列<pthread.h> 线程<sched.h> 执行调度<semaphore.h> 信号量<spawn.h> 实时spawn接口<stropts.h> XSI STREAMS接口<trace.h> 事件跟踪
C99增加的部分

#include <complex.h> 复数处理

#include <fenv.h> 浮点环境

#include <inttypes.h> 整数格式转换

#include <stdbool.h> 布尔环境

#include <stdint.h> 整型环境

#include <tgmath.h> 通用类型数学宏
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