How to make g search for header files in a specific directory

Question

I have a project  a library  that is subdivided into a few directories with code in them  I d like to to have g   search for header files in the project s root directory  so I can avoid different include paths for same header files across multiple source files   Mainly  the root  directory has sub-directories A   B  and C   all of which have  hpp and  cpp files inside  If some source file in A wanted to include file hpp  which was in B  it would have to do it like this   include     B file hpp   Same for another source file that was in C  But  if A itself had sub-directories with files that needed file hpp  then  it would be inconsistent and would cause errors if I decided to move files  because the include path would be        B file hpp     Also  this would need to work from other projects as well  which reside outside of root   I already know that there is an option to manually copy all my header files into a default-search directory  but I d like to do this the way I described   Edit  all programs using the library must compile only with g   prog cpp lib a -o prog  That means permanently setting the include path for g

User · Answer

Headers included with  include  lt   will be searched in all default directories   but you can also add your own location in the search path with -I command line arg   I saw your edit you could install your headers in default locations usually     usr local include  libdir gcc target version include   usr target include   usr include   Confirm with compiler docs though

User · Answer

it s simple  use the  -B  option to add  h files  dir to search path    E g  g   -B  header file h your cpp -o bin your command

User · Answer

gcc -I path -L path    -I  path path to include   gcc will find  h files in this path -L  path contains library files   a   so

User · Answer

A code cpp   include  lt B file hpp gt    A a code2 cpp   include  lt B file hpp gt    Compile using   g   -I  your source root  your source root A code cpp g   -I  your source root  your source root A a code2 cpp   Edit   You can use environment variables to change the path g   looks for header files  From man page      Some additional environments variables affect the behavior of the   preprocessor      CPATH    C INCLUDE PATH    CPLUS INCLUDE PATH    OBJC INCLUDE PATH       Each variable s value is a list of directories separated by a special character  much like PATH  in which to look for header   files  The special character   PATH SEPARATOR   is target-dependent and determined at GCC build time   For Microsoft Windows-based targets it   is a semicolon  and for almost all other targets it is a colon       CPATH specifies a list of directories to be searched as if specified with -I  but after any paths given with -I options on the   command line   This              environment variable is used regardless of which language is being preprocessed       The remaining environment variables apply only when preprocessing the particular language indicated   Each specifies a   list of directories to be              searched as if specified with -isystem  but after any paths given with -isystem options on the command line       In all these variables  an empty element instructs the compiler to search its current working directory   Empty elements can   appear at the beginning              or end of a path   For instance  if the value of CPATH is    special include   that has the same effect as -I    -I special include    There are many ways you can change an environment variable  On bash prompt you can do this     export CPATH  your source root   g    your source root A code cpp   g    your source root A a code2 cpp   You can of course add this in your Makefile etc

[directory] How to make g++ search for header files in a specific directory?

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