c++ - 如何使用 CMake 链接多个库

Question

我有一些与 DCMTK 有关的代码。如果我从命令行使用 g++，我可以成功地构建和运行它。这是代码:

#include "dcmtk/config/osconfig.h"
#include "dcmtk/dcmdata/dctk.h"

int main()
{
DcmFileFormat fileformat;
OFCondition status = fileformat.loadFile("test.dcm");
if (status.good())
{
   OFString patientsName;
   if (fileformat.getDataset()->findAndGetOFString(DCM_PatientsName, patientsName).good())
   {
      cout << "Patient's Name: " << patientsName << endl;
   } else
     cerr << "Error: cannot access Patient's Name!" << endl;
} else
cerr << "Error: cannot read DICOM file (" << status.text() << ")" << endl;
return 0;
}

这是构建命令:

g++ testeapp.cxx -DHAVE_CONFIG_H -I/path_to_dcmtk/include -L/path_to_dcmtk/lib -pthread -ldcmdata -lz -loflog -lofstd -o main

我想制作一个 CMakeLists.txt 以在 Kdevelop 中构建它。这是我目前拥有的:

    # Configure toplevel directories
    SET( PREFIX     ${CMAKE_INSTALL_PREFIX} CACHE PATH "Top level.")
    SET( INCLUDEDIR ${PREFIX}/include       CACHE PATH "Include files.")
    SET( LIBDIR     ${PREFIX}/lib           CACHE PATH "Libraries.")
    FIND_PACKAGE ( Threads REQUIRED )
    # Configure DCMTK
    FIND_PATH( DINIFTI_DCMTK_INCLUDE dcmtk
               PATHS ${INCLUDEDIR}
               PATH_SUFFIXES dcmtk
               DOC "Path to the DCMTK headers." )
    FIND_LIBRARY(DINIFTI_DCMTK_LIB NAMES dcmdata ofstd oflog 
                 HINTS ${LIBDIR} ${LIBDIR})
TARGET_LINK_LIBRARIES( dinifti ${DINIFTI_DCMTK_LIB}
                               ${DINIFTI_ZNZ_LIB}
                               ${CMAKE_THREAD_LIBS_INIT}
                               z )             

但是当我构建它时，它有这个错误:

/usr/local/lib/libdcmdata.a(dcfilefo.o): In function `DcmFileFormat::remove(DcmItem*)':
dcfilefo.cc:(.text+0x1788): undefined reference to `log4cplus::Logger::forcedLog(int, OFString const&, char const*, int, char const*) const'

你能帮我解决这个错误吗？谢谢。

Answer 1

看起来您期望的是 find_library调用以使用 3 个独立的库填充变量 DINIFTI_DCMTK_LIB。

这不是 find_library 的工作方式。 NAMES 之后的不同参数表示单个库可以 调用的所有不同名称。这允许命令跨平台工作，其中同一个库在不同平台上可以被称为不同的东西。

一个小问题是您可能更喜欢在这里使用 PATHS 而不是 HINTS。形成文档:

... the HINTS option ... should be paths computed by system introspection, such as a hint provided by the location of another item already found. Hard-coded guesses should be specified with the PATHS option.

我想你想要的更像是:

find_library(DINIFTI_DCMTK_LIB NAMES dcmdata PATHS ${LIBDIR})
find_library(OFSTD_LIB NAMES ofstd PATHS ${LIBDIR})
find_library(OFLOG_LIB NAMES oflog PATHS ${LIBDIR})
target_link_libraries(dinifti ${DINIFTI_DCMTK_LIB}
                              ${OFLOG_LIB}
                              ${OFSTD_LIB}
                              ${DINIFTI_ZNZ_LIB}
                              ${CMAKE_THREAD_LIBS_INIT}
                              z)