对于使用 gcc编译时候,有时候回去查看相关的头文件的声明
但是对于有些头文件存放位置,却不在通常的 /usr/include目录下,比如 stdarg.h
可以通过以下方式来查看 GCC编译时候所使用的默认搜索路径
首先,使用 gcc --help来查看 gcc支持的命令
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[martin@linux-2.6.11]$ gcc --help
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Usage: gcc [options] file...
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Options:
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-pass-exit-codes Exit with highest error code from a phase
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--help Display this information
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--target-help Display target specific command line options
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--help={common|optimizers|params|target|warnings|[^]{joined|separate|undocumented}}[,...]
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Display specific types of command line options
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(Use '-v --help' to display command line options of sub-processes)
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--version Display compiler version information
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-dumpspecs Display all of the built in spec strings
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-dumpversion Display the version of the compiler
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-dumpmachine Display the compiler's target processor
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-print-search-dirs Display the directories in the compiler's search path
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-print-libgcc-file-name Display the name of the compiler's companion library
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-print-file-name= Display the full path to library
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-print-prog-name= Display the full path to compiler component
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-print-multiarch Display the target's normalized GNU triplet, used as
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a component in the library path
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-print-multi-directory Display the root directory for versions of libgcc
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-print-multi-lib Display the mapping between command line options and
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multiple library search directories
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-print-multi-os-directory Display the relative path to OS libraries
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-print-sysroot Display the target libraries directory
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-print-sysroot-headers-suffix Display the sysroot suffix used to find headers
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-Wa,<options> Pass comma-separated <options> on to the assembler
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-Wp,<options> Pass comma-separated <options> on to the preprocessor
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-Wl,<options> Pass comma-separated <options> on to the linker
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-Xassembler <arg> Pass <arg> on to the assembler
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-Xpreprocessor <arg> Pass <arg> on to the preprocessor
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-Xlinker <arg> Pass <arg> on to the linker
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-save-temps Do not delete intermediate files
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-save-temps=<arg> Do not delete intermediate files
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-no-canonical-prefixes Do not canonicalize paths when building relative
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prefixes to other gcc components
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-pipe Use pipes rather than intermediate files
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-time Time the execution of each subprocess
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-specs=<file> Override built-in specs with the contents of <file>
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-std=<standard> Assume that the input sources are for <standard>
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--sysroot=<directory> Use <directory> as the root directory for headers
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and libraries
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-B <directory> Add <directory> to the compiler's search paths
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-v Display the programs invoked by the compiler
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-### Like -v but options quoted and commands not executed
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-E Preprocess only; do not compile, assemble or link
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-S Compile only; do not assemble or link
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-c Compile and assemble, but do not link
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-o Place the output into
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-pie Create a position independent executable
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-shared Create a shared library
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-x Specify the language of the following input files
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Permissible languages include: c c++ assembler none
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'none' means revert to the default behavior of
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guessing the language based on the file's extension
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Options starting with -g, -f, -m, -O, -W, or --param are automatically
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passed on to the various sub-processes invoked by gcc. In order to pass
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other options on to these processes the -W<letter> options must be used.
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For bug reporting instructions, please see:
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<file:///usr/share/doc/gcc-4.8/README.Bugs>.
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[martin@linux-2.6.11]$
其中有个
print-search-dirs,会罗列以下的搜罗目录,包括lib,.h文件等等(对比后发现是有重复的)
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[martin@linux-2.6.11]$ gcc -print-search-dirs
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install: /usr/lib/gcc/i686-linux-gnu/4.8/
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programs: =/usr/lib/gcc/i686-linux-gnu/4.8/:/usr/lib/gcc/i686-linux-gnu/4.8/:/usr/lib/gcc/i686-linux-gnu/:/usr/lib/gcc/i686-linux-gnu/4.8/:/usr/lib/gcc/i686-linux-gnu/:/usr/lib/gcc/i686-linux-gnu/4.8/../../../../i686-linux-gnu/bin/i686-linux-gnu/4.8/:/usr/lib/gcc/i686-linux-gnu/4.8/../../../../i686-linux-gnu/bin/i386-linux-gnu/:/usr/lib/gcc/i686-linux-gnu/4.8/../../../../i686-linux-gnu/bin/
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libraries: =/usr/lib/gcc/i686-linux-gnu/4.8/:/usr/lib/gcc/i686-linux-gnu/4.8/../../../../i686-linux-gnu/lib/i686-linux-gnu/4.8/:/usr/lib/gcc/i686-linux-gnu/4.8/../../../../i686-linux-gnu/lib/i386-linux-gnu/:/usr/lib/gcc/i686-linux-gnu/4.8/../../../../i686-linux-gnu/lib/../lib/:/usr/lib/gcc/i686-linux-gnu/4.8/../../../i686-linux-gnu/4.8/:/usr/lib/gcc/i686-linux-gnu/4.8/../../../i386-linux-gnu/:/usr/lib/gcc/i686-linux-gnu/4.8/../../../../lib/:/lib/i686-linux-gnu/4.8/:/lib/i386-linux-gnu/:/lib/../lib/:/usr/lib/i686-linux-gnu/4.8/:/usr/lib/i386-linux-gnu/:/usr/lib/../lib/:/usr/lib/gcc/i686-linux-gnu/4.8/../../../../i686-linux-gnu/lib/:/usr/lib/gcc/i686-linux-gnu/4.8/../../../:/lib/:/usr/lib/
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[martin@linux-2.6.11]$
头文件的搜索,可以直接使用 -print-prog-name=
来实现
1. 对于 c的头文件,使用-print-prog-name=cc1
2. 对于c++的头文件, 使用 -print-prog-name=cc1plus
如果直接使用 gcc -print-prog-name=cc1,会打印 cc1的程序路径,比如
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[martin@linux-2.6.11]$ gcc -print-prog-name=cc1
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/usr/lib/gcc/i686-linux-gnu/4.8/cc1
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[martin@linux-2.6.11]$
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[martin@linux-2.6.11]$ gcc -print-prog-name=cc1plus
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/usr/lib/gcc/i686-linux-gnu/4.8/cc1plus
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[martin@linux-2.6.11]$
但是不会显示具体的搜索路径。如果需要显示路径,则需要执行该cc1程序,附带使用 -v选项(cc1有很多其他的选项,没有研究使用方法)
执行的方式有两种:
1. 直接执行该文件
2. 借助shell中的 `来实现 gcc -print-prog-name=cc1的程序
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[martin@linux-2.6.11]$ `gcc -print-prog-name=cc1` -v
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ignoring nonexistent directory "/usr/lib/gcc/i686-linux-gnu/4.8/../../../../i686-linux-gnu/include"
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#include "..." search starts here:
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#include <...> search starts here:
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/usr/lib/gcc/i686-linux-gnu/4.8/include
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/usr/local/include
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/usr/lib/gcc/i686-linux-gnu/4.8/include-fixed
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/usr/include
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End of search list.
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^C^C
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[martin@linux-2.6.11]$
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[martin@linux-2.6.11]$ /usr/lib/gcc/i686-linux-gnu/4.8/cc1 -v
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ignoring nonexistent directory "/usr/lib/gcc/i686-linux-gnu/4.8/../../../../i686-linux-gnu/include"
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#include "..." search starts here:
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#include <...> search starts here:
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/usr/lib/gcc/i686-linux-gnu/4.8/include
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/usr/local/include
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/usr/lib/gcc/i686-linux-gnu/4.8/include-fixed
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/usr/include
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End of search list.
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^C
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[martin@linux-2.6.11]$
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[martin@linux-2.6.11]$
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[martin@linux-2.6.11]$ `gcc -print-prog-name=cc1plus` -v
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ignoring nonexistent directory "/usr/lib/gcc/i686-linux-gnu/4.8/../../../../i686-linux-gnu/include"
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#include "..." search starts here:
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#include <...> search starts here:
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/usr/include/c++/4.8
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/usr/include/i386-linux-gnu/c++/4.8
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/usr/include/c++/4.8/backward
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/usr/lib/gcc/i686-linux-gnu/4.8/include
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/usr/local/include
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/usr/lib/gcc/i686-linux-gnu/4.8/include-fixed
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/usr/include
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End of search list.
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^C
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[martin@linux-2.6.11]$
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[martin@linux-2.6.11]$ /usr/lib/gcc/i686-linux-gnu/4.8/cc1plus -v
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ignoring nonexistent directory "/usr/lib/gcc/i686-linux-gnu/4.8/../../../../i686-linux-gnu/include"
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#include "..." search starts here:
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#include <...> search starts here:
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/usr/include/c++/4.8
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/usr/include/i386-linux-gnu/c++/4.8
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/usr/include/c++/4.8/backward
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/usr/lib/gcc/i686-linux-gnu/4.8/include
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/usr/local/include
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/usr/lib/gcc/i686-linux-gnu/4.8/include-fixed
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/usr/include
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End of search list.
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^C
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[martin@linux-2.6.11]$
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