ofsp2025-03

...
int main() // 省略参数列表
{
	...
}

...
int main(int argc, char *argv[]) {}
// 或者
int main(int argc, char **argv) {}

#include <iostream>

int main(int argc, char *argv[])
{
    std::cout << "Number of arguments = " << argc << std::endl;

    for (int i=0; i<argc; ++i)
    {
        std::cout << "Argument " << i << ": "
            << argv[i] << std::endl;
    }

    return 0;
}

// Construct from (int argc, char* argv[]),
// - use argList::argsMandatory() to decide on checking command arguments.
// - check validity of the options

Foam::argList args(argc, argv); // 基于argc和argv，构造argList类型的args对象
if (!args.checkRootCase()) // 如果检查命令行参数（算例路径）错误
{
    Foam::FatalError.exit(); // 报错退出
}

// User can also perform checks on otherwise optional arguments.
// Eg,
//
//  if (!args.check(true, false))
//  {
//      Foam::FatalError.exit();
//  }

// Force dlOpen of FOAM_DLOPEN_LIBS (principally for Windows applications)
#include "foamDlOpenLibs.H" // 兼容性处理，无需深究

...
class argList
{
	...
public:
	...
	// 基于参数的构造函数
	argList
	(
		int& argc, // 主函数参数个数
		char**& argv, // 主函数参数的指针
		bool checkArgs = argList::argsMandatory(),
		bool checkOpts = true,
		bool initialise = true
	);
	...
	//- Check root path and case path // 检查根目录路径和算例路径
        bool checkRootCase() const;
    ...
...

...
bool Foam::argList::checkRootCase() const
{
    if (!fileHandler().isDir(rootPath())) // 如果根目录路径有问题，则报错
    {
        FatalError
            << executable_
            << ": cannot open root directory " << rootPath()
            << endl;

        return false;
    }

    const fileName pathDir(fileHandler().filePath(path(), false));

	// 如果算例路径有问题，则报错
    if (checkProcessorDirectories_ && pathDir.empty() && Pstream::master())
    {
        // Allow non-existent processor directories on sub-processes,
        // to be created later (e.g. redistributePar)
        FatalError
            << executable_
            << ": cannot open case directory " << path()
            << endl;

        return false;
    }

    return true;
}
...

#include "fvCFD.H"

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

int main(int argc, char *argv[])
{
    argList::addNote
    (
        "Demonstrates how to handle command line options.\n\n"
        "Application arguments:\n"
        "----------------------\n"
        "       mathLib - Eigen/GSL/Armodillo/BLAS\n"
        "       level   - computation speedup\n"
    );

    #include "setRootCase.H" // 放在命令行相关代码的最后
    #include "createTime.H"

    // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

    Info<< nl;
    runTime.printExecutionTime(Info);

    Info<< "End\n" << endl;

    return 0;
}


// ************************************************************************* //

#include "fvCFD.H"

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

int main(int argc, char *argv[])
{
    argList::addNote
    (
        "Demonstrates how to handle command line options.\n\n"
        "Application arguments:\n"
        "----------------------\n"
        "       mathLib - Eigen/GSL/Armodillo/BLAS\n"
        "       level   - computation speedup\n"
    );

    argList::validArgs.append("mathLib");
    argList::validArgs.append("level");
    // 将应用参数增补到主函数参数列表里
    // 在运行程序时，这两个参数是需要强制给定的

    #include "setRootCase.H" // 构造OpenFOAM的argList类型的args对象
    #include "createTime.H"

    #include "createMesh.H"

	// args的第0参数是程序名本身
    const word args1 = args[1]; // args第1参数就是增补的第1个参数
    const scalar args2 = args.get<scalar>(2); // 增补的第2个参数


	// 显示参数
    Info<< "Solver setup: " << nl
        << "    use     : " << args1 << nl
        << "    speedup : " << args2 << nl
        << nl << endl;

    // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

    Info<< nl;
    runTime.printExecutionTime(Info);

    Info<< "End\n" << endl;

    return 0;
}


// ************************************************************************* //

#include "fvCFD.H"

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

int main(int argc, char *argv[])
{
    argList::addNote
    (
        "Demonstrates how to handle command line options.\n\n"
        "Application arguments:\n"
        "----------------------\n"
        "       mathLib - Eigen/GSL/Armodillo/BLAS\n"
        "       level   - computation speedup\n"
    );

	// 应用参数要在 setRootCase.H 构造 args 之前
    argList::validArgs.append("mathLib");
    argList::validArgs.append("level");

	// 应用选项也要在 setRootCase.H 构造 args 之前
    argList::addOption
    (
        "dict",
        "word",
        "Use addtional dictionary (just for example)"
    );

    argList::addOption
    (
        "nPrecision",
        "label",
        "Set the precision level (just for example)"
    );

    argList::addBoolOption
    (
        "log",
        "output the log"
    );

	// setRootCase.H 将构造argList类型的args对象
    #include "setRootCase.H"
    #include "createTime.H"

    #include "createMesh.H"

    const word args1 = args[1];
    const scalar args2 = args.get<scalar>(2);

    Info<< "Solver setup: " << nl
        << "    use     : " << args1 << nl
        << "    speedup : " << args2 << nl
        << nl << endl;

	// 创建dict_并给默认初始值
    fileName dict_("./system/myDict");
    if (args.found("dict"))
    {
        args.readIfPresent("dict",dict_);
        // 如果使用了 -dict 选项，则使用 -dict 后的值
        // 也许会有同学疑问上面这句代码为什么能读取 -dict 后的值并传给 dict_
        // 建议先不要深究，以后熟悉C++了可以翻阅OpenFOAM更底层的源代码
        Info<< "Reading myDict " << endl;
    }
    Info<< "Dictionary from " << dict_ << nl << endl;

	// 创建 label 类型的对象并给默认初始值
    label nPrecision_(6);
    args.readIfPresent("nPrecision",nPrecision_);
    Info<< "Precision is " << nPrecision_ << endl;

    const bool log_ = args.found("log");
    if (log_)
    {
        Info<< "Output the logs" << endl;
    }
    // 只要使用 -log 选项，就会执行一些方法，比如这里的输出


    // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

    Info<< nl;
    runTime.printExecutionTime(Info);

    Info<< "End\n" << endl;

    return 0;
}


// ************************************************************************* //