gcc:gcc include path gccにおけるincludeファイルの検索パス
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we saw how to link to a program with functions in the C math library ‘libm.a’, using the short-cut option -lm and the header file ‘math.h’.
A common problem when compiling a program using library header files is the error:
This occurs if a header file is not present in the standard include file directories used by gcc. A similar problem can occur for libraries:
This happens if a library used for linking is not present in the standard library directories used by gcc.
By default, gcc searches the following directories for header files:
and the following directories for libraries:
The list of directories for header files is often referred to as the include path, and the list of directories for libraries as the library search path or link path.
The directories on these paths are searched in order, from first to last in the two lists above.(7) For example, a header file found in ‘/usr/local/include’ takes precedence over a file with the same name in ‘/usr/include’. Similarly, a library found in ‘/usr/local/lib’ takes precedence over a library with the same name in‘/usr/lib’.
When additional libraries are installed in other directories it is necessary to extend the search paths, in order for the libraries to be found. The compiler options-I and -L add new directories to the beginning of the include path and library search path respectively.
gcc検索のパスは、gccをコンパイルする際に指定したパスに依存します.gccをコンパイルするときに以下のように変更すると、gccリファレンスパスが変更されます.
Change the StartFile Spec and Standard Include Dir so that GCC looks in /tools:
Now alter gcc's c preprocessor's default include search path to use /tools only:
このときコンパイルされたgccツールは、デフォルトのinclude検索パスが/tools/includeになります.
we saw how to link to a program with functions in the C math library ‘libm.a’, using the short-cut option -lm and the header file ‘math.h’.
A common problem when compiling a program using library header files is the error:
FILE.h: No such file or directory
This occurs if a header file is not present in the standard include file directories used by gcc. A similar problem can occur for libraries:
/usr/bin/ld: cannot find libraryThis happens if a library used for linking is not present in the standard library directories used by gcc.
By default, gcc searches the following directories for header files:
/usr/local/include/
/usr/include/
and the following directories for libraries:
/usr/local/lib/
/usr/lib/
The list of directories for header files is often referred to as the include path, and the list of directories for libraries as the library search path or link path.
The directories on these paths are searched in order, from first to last in the two lists above.(7) For example, a header file found in ‘/usr/local/include’ takes precedence over a file with the same name in ‘/usr/include’. Similarly, a library found in ‘/usr/local/lib’ takes precedence over a library with the same name in‘/usr/lib’.
When additional libraries are installed in other directories it is necessary to extend the search paths, in order for the libraries to be found. The compiler options-I and -L add new directories to the beginning of the include path and library search path respectively.
gcc検索のパスは、gccをコンパイルする際に指定したパスに依存します.gccをコンパイルするときに以下のように変更すると、gccリファレンスパスが変更されます.
Change the StartFile Spec and Standard Include Dir so that GCC looks in /tools:
echo -en '#undef STANDARD_INCLUDE_DIR
#define STANDARD_INCLUDE_DIR "/tools/include/"
' >> gcc/config/linux.h
echo -en '
#undef STANDARD_STARTFILE_PREFIX_1
#define STANDARD_STARTFILE_PREFIX_1 "/tools/lib/"
' >> gcc/config/linux.h
echo -en '
#undef STANDARD_STARTFILE_PREFIX_2
#define STANDARD_STARTFILE_PREFIX_2 ""
' >> gcc/config/linux.hNow alter gcc's c preprocessor's default include search path to use /tools only:
cp -v gcc/Makefile.in{,.orig}
sed -e "s@\(^CROSS_SYSTEM_HEADER_DIR =\).*@\1 /tools/include@g" \
gcc/Makefile.in.orig > gcc/Makefile.inこのときコンパイルされたgccツールは、デフォルトのinclude検索パスが/tools/includeになります.