How can this header be seen?

Question

I've been trying to understand CMake, and recently I've stumbled upon the CLion ide. So far, it's helped out a bit. In trying to get google test integrated with CLion, I cloned this github repo.

However, I don't understand how the .cpp files that hold the test method can "see" the header files for the library, when they are at the wrong relative path!

Calendar_check.cpp:

//
// Created by AK on 13/10/15.
//

#include "gtest/gtest.h"

#include "GregorianCalendar.h"
#include "JulianCalendar.h"
///Code that runs tests, not important for this question

However, the directory structure is set up like so:

Seeing how the project is set up, shouldn't the calendar_check.cpp file's #include statement read

#include "../../calendars/GregorianCalendar.h" #include "../../calendars/JulianCalendar.h" instead?

I know static libraries don't have header files with them, so I don't understand how the calendar_test.cpp file can know where those headers are using the path they use.

Here are the CMakeLists.txt files:

Root:

cmake_minimum_required(VERSION 3.1)
project(Calendar)

#add_definitions(-std=c++11 --target=x86_64-linux-gnu)
#set(CMAKE_CXX_STANDARD 11)

set(SOURCE_FILES main.cpp)
add_executable(calendar_run ${SOURCE_FILES})

include_directories(calendars)

add_subdirectory(calendars)
add_subdirectory(calendars_tests)


target_link_libraries(calendar_run calendars)

root/calendars:

project(calendars)

set(HEADER_FILES
        calendar_defs.h
        General.h
        GregorianCalendar.h
        JulianCalendar.h
        IslamicCalendar.h
        HebrewCalendar.h
    )

set(SOURCE_FILES
        calendar_defs.cpp
        Calendar.cpp
        General.cpp
        GregorianCalendar.cpp
        JulianCalendar.cpp
        IslamicCalendar.cpp
        HebrewCalendar.cpp
    )

add_library(calendars STATIC ${SOURCE_FILES} ${HEADER_FILES})

root/calendar_tests:

project(calendars_tests)

add_subdirectory(lib/gtest-1.7.0)
add_subdirectory(basic_tests)

root/calendar_tests/basic_tests:

include_directories(${gtest_SOURCE_DIR}/include ${gtest_SOURCE_DIR})

add_executable(runBasicCalendarTests
        basic_check.cpp
        calendar_check.cpp)

target_link_libraries(runBasicCalendarTests gtest gtest_main)
target_link_libraries(runBasicCalendarTests calendars)

IDEs put the header files in your programs in a specific place. For most IDEs, you do not need to type the whole file path, unless you've moved the file out of the default location, because the IDE already knows where it is. — , Jul 11 '16 at 23:44

score 1 · Accepted Answer · edited May 23 '17 at 12:32

You must read this answer from this question: What is the difference between #include < filename> and #include “filename”?

in special, when piCookie says:

A preprocessing directive of the form

#include "q-char-sequence" new-line

causes the replacement of that directive by the entire contents of the source file identified by the specified sequence between the " delimiters. The named source file is searched for in an implementation-defined manner. If this search is not supported, or if the search fails, the directive is reprocessed as if it read

#include <h-char-sequence> new-line

with the identical contained sequence (including > characters, if any) from the original directive.

After you finished the reading note that at this line in CMakeLists.txt:

include_directories(calendars)

you are asking cmake to include calendars directory to include search path.

How can this header be seen?

1 Answers1