On Thu, Dec 14, 2023 at 1:27 AM 2111191--- via petsc-users < [email protected]> wrote:

Dear SLEPc Developers,

I a am student from Tongji University. Recently I am trying to write a c++ program for matrix solving, which requires importing the PETSc library that you have developed. However a lot of errors occur in the cpp file when I use #include <petscts.h> directly. I also try to use extern "C" but it gives me the error in the picture below. Is there a good way to use the PETSc library in a c++ program? (I compiled using cmake and my compiler is g++ (GCC) 4.8.5 20150623 (Red Hat 4.8.5-44)).

My cmakelists.txt is:

cmake_minimum_required(VERSION 3.1.0)

set(CMAKE_INSTALL_RPATH_USE_LINK_PATH TRUE)

set(PETSC $ENV{PETSC_DIR}/$ENV{PETSC_ARCH}) set(SLEPC $ENV{SLEPC_DIR}/$ENV{PETSC_ARCH}) set(ENV{PKG_CONFIG_PATH} ${PETSC}/lib/pkgconfig:${SLEPC}/lib/pkgconfig)

set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11") set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=c99")

project(test)

add_executable(${PROJECT_NAME} eigen_test2.cpp) find_package(PkgConfig REQUIRED)

pkg_search_module(PETSc REQUIRED IMPORTED_TARGET PETSc) target_link_libraries(${PROJECT_NAME} PkgConfig::PETSc)

The testing code is:eigen_test2.cpp

First, get rid of the "extern C" in front of the headers. Thanks, Matt

extern "C"{ //#include <petsc.h> #include <petscts.h> #include <petscdm.h> #include <petscdmda.h> #include <petscdraw.h> }

int main(int argc,char **argv) { return 0; }

Best regards

Weijie Xu

-- What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead. -- Norbert Wiener https://www.cse.buffalo.edu/~knepley/ <http://www.cse.buffalo.edu/~knepley/>