LinuxQuestions.org - object files, compiling, location

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object files, compiling, location

When you compile a program with standard header files like <iostream> it looks to me like the compiler never compiles any .cpp files for them so I assume the .o files are all stored somewhere so all the compiler does is link them. Is that right?

I did this:

Code:

root@inferno:/home/icecube# find / -name iostream

/usr/include/boost/tr1/tr1/iostream

/usr/include/c++/4.2.4/iostream

/usr/local/boost_1_38_0/boost/tr1/tr1/iostream

/usr/local/include/boost-1_38/boost/tr1/tr1/iostream

root@inferno:/home/icecube#

And I installed boost myself so I guess /usr/include/c++/4.2.4 is where the isostream header file is at.

How does g++ know where to look for standard header files? Does it use the same PATH ($PATH?) variable (I can't remember what it's called) that the shell uses when tries to find executable files like ls?

1) $PATH is for executable's :/bin:/usr/bin:/usr/local/bin etc.

2) LD_LIBRARY_PATH is for libraries (:/lib:/usr/lib: .. etc.)

3) c++ (g++), gcc has a 'build in' path, knowing where to look :

when gcc, g++ is compiled with '--prefix=/usr', the path for the
includes is ( for g++) /usr/include/c++/4.x.x/ ....
for the '4.x.x' versions.
.....