C++、C2447 '{' : missing function header (old-style format list? )、win32 和 long

Question

我在基于现有学习代码构建解决方案时遇到错误。我定义的预处理器是 Win32(应该是)，代码本身来自 https://www.nayuki.io/page/bitcoin-cryptography-library .该错误似乎是由 long 值创建的，该值可能是导致此错误的原因(使用的是 win32 而不是 win64)。我试图克服以不同方式编写它(使用 long/ulong/int)但没有成功。

static long long opsCount;

void countOps(long n){
    opsCount += n;
}

有什么建议可以用其他方式编写并解决错误列表中的恶劣天气吗？

/* 
 * A runnable main program that calculates and prints the approximate
 * number of 32-bit arithmetic operations needed to perform
 * elliptic curve point multiplication, in this C++ implementation.
 * 
 * Bitcoin cryptography library
 * Copyright (c) Project Nayuki
 * 
 * https://www.nayuki.io/page/bitcoin-cryptography-library
 * https://github.com/nayuki/Bitcoin-Cryptography-Library
 */

#include <cstddef>
#include <cstdlib>
#include <iostream>
#include <string>
#include "CountOps.hpp"
#include "CurvePoint.hpp"
#include "Ecdsa.hpp"
#include "FieldInt.hpp"
#include "Sha256.hpp"
#include "Sha256Hash.hpp"
#include "Uint256.hpp"


static long long opsCount;


void countOps(long n){
    opsCount += n;
}



static void printOps(const char *name);
static void doUint256();
static void doFieldInt();
static void doCurvePoint();
static void doEcdsa();


int main() {
    doUint256();
    doFieldInt();
    doCurvePoint();
    doEcdsa();
    return EXIT_SUCCESS;
}


static void doUint256() {
    {
        Uint256 x = Uint256::ONE;
        Uint256 y = Uint256::ONE;
        opsCount = 0;
        x.replace(y, 1);
        printOps("uiReplace");
    }
    {
        Uint256 x = Uint256::ONE;
        Uint256 y = Uint256::ONE;
        opsCount = 0;
        x.swap(y, 1);
        printOps("uiSwap");
    }
    {
        Uint256 x = Uint256::ONE;
        Uint256 y = Uint256::ONE;
        opsCount = 0;
        x == y;
        printOps("uiEquals");
    }
    {
        Uint256 x = Uint256::ONE;
        Uint256 y = Uint256::ONE;
        opsCount = 0;
        x < y;
        printOps("uiLessThan");
    }
    {
        Uint256 x = Uint256::ONE;
        Uint256 y = Uint256::ONE;
        opsCount = 0;
        x.add(y);
        printOps("uiAdd");
    }
    {
        Uint256 x = Uint256::ONE;
        Uint256 y = Uint256::ONE;
        opsCount = 0;
        x.subtract(y);
        printOps("uiSubtract");
    }
    {
        Uint256 x = Uint256::ONE;
        opsCount = 0;
        x.shiftLeft1();
        printOps("uiShiftLeft1");
    }
    {
        Uint256 x = Uint256::ONE;
        opsCount = 0;
        x.shiftRight1();
        printOps("uiShiftRight1");
    }
    {
        Uint256 x = Uint256::ONE;
        Uint256 y = CurvePoint::ORDER;
        opsCount = 0;
        x.reciprocal(y);
        printOps("uiReciprocal");
    }
    std::cout << std::endl;
}


static void doFieldInt() {
    {
        FieldInt x(Uint256::ONE);
        FieldInt y(Uint256::ONE);
        opsCount = 0;
        x.replace(y, 1);
        printOps("fiReplace");
    }
    {
        FieldInt x(Uint256::ONE);
        FieldInt y(Uint256::ONE);
        opsCount = 0;
        x == y;
        printOps("fiEquals");
    }
    {
        FieldInt x(Uint256::ONE);
        FieldInt y(Uint256::ONE);
        opsCount = 0;
        x < y;
        printOps("fiLessThan");
    }
    {
        FieldInt x(Uint256::ONE);
        FieldInt y(Uint256::ONE);
        opsCount = 0;
        x.add(y);
        printOps("fiAdd");
    }
    {
        FieldInt x(Uint256::ONE);
        FieldInt y(Uint256::ONE);
        opsCount = 0;
        x.subtract(y);
        printOps("fiSubtract");
    }
    {
        FieldInt x(Uint256::ONE);
        opsCount = 0;
        x.multiply2();
        printOps("fiMultiply2");
    }
    {
        FieldInt x(Uint256::ONE);
        FieldInt y(Uint256::ONE);
        opsCount = 0;
        x.multiply(y);
        printOps("fiMultiply");
    }
    {
        FieldInt x(Uint256::ONE);
        opsCount = 0;
        x.square();
        printOps("fiSquare");
    }
    {
        FieldInt x(Uint256::ONE);
        opsCount = 0;
        x.reciprocal();
        printOps("fiReciprocal");
    }
    std::cout << std::endl;
}


static void doCurvePoint() {
    {
        CurvePoint x = CurvePoint::G;
        CurvePoint y = CurvePoint::G;
        opsCount = 0;
        x.replace(y, 1);
        printOps("cpReplace");
    }
    {
        CurvePoint x = CurvePoint::G;
        opsCount = 0;
        x.isZero();
        printOps("cpIsZero");
    }
    {
        CurvePoint x = CurvePoint::G;
        CurvePoint y = CurvePoint::G;
        opsCount = 0;
        x == y;
        printOps("cpEquals");
    }
    {
        CurvePoint x = CurvePoint::G;
        opsCount = 0;
        x.twice();
        printOps("cpTwice");
    }
    {
        CurvePoint x = CurvePoint::G;
        CurvePoint y = CurvePoint::G;
        opsCount = 0;
        x.add(y);
        printOps("cpAdd");
    }
    {
        CurvePoint x = CurvePoint::G;
        Uint256 y = Uint256::ONE;
        opsCount = 0;
        x.multiply(y);
        printOps("cpMultiply");
    }
    {
        CurvePoint x = CurvePoint::G;
        opsCount = 0;
        x.normalize();
        printOps("cpNormalize");
    }
    {
        CurvePoint x = CurvePoint::G;
        opsCount = 0;
        x.isOnCurve();
        printOps("cpIsOnCurve");
    }
    std::cout << std::endl;
}


static void doEcdsa() {
    {
        Uint256 privKey = Uint256::ONE;
        Sha256Hash msgHash = Sha256::getHash(nullptr, 0);
        Uint256 nonce = Uint256::ONE;
        Uint256 outR, outS;
        opsCount = 0;
        Ecdsa::sign(privKey, msgHash, nonce, outR, outS);
        printOps("edSign");
    }
    {
        CurvePoint pubKey = CurvePoint::G;
        Sha256Hash msgHash = Sha256::getHash(nullptr, 0);
        Uint256 r = Uint256::ONE;
        Uint256 s = Uint256::ONE;
        opsCount = 0;
        Ecdsa::verify(pubKey, msgHash, r, s);
        printOps("edVerify");
    }
    std::cout << std::endl;
}


static void printOps(const char *name) {
    std::string s = std::to_string(opsCount);
    while (s.size() < 9)
        s.insert(0, " ", 1);
    for (std::size_t i = s.size(); i >= 4; i -= 3)
        s.insert(i - 3, " ", 1);
    std::cout << s << "  " << name << std::endl;
}

错误如下:

Answer 1

为了将来引用，您应该努力使您的示例成为一个好的 Minimal, Reproducible Example .这不仅会增加您在 Stack Overflow 上获得回复的机会，而且很可能会成功，因此您可以开始自己解决问题。

例如，这是您遇到问题的单个函数:

#define countOps(n)
static long long opsCount;
void countOps(long n){
    opsCount += n;
}

如果您尝试在 .cpp 文件中编译它，它会工作，但会提示缺少入口点。所以，#include 一定是导致问题的原因。明显的候选者是 CountOps.hpp 声明它的地方。在这种情况下，除非您 #define COUNT_OPS，否则 header 将只是

#define countOps(n)

因此，如果我们将这两部分放在一起，我们就会得到一个最小的、可重现的编译错误示例:

#define countOps(n)
static long long opsCount;
void countOps(long n){
    opsCount += n;
}

换句话说，包含的文件试图将 countOps 函数#define 置为空，通过实现它，预处理器将您的代码转换为

static long long opsCount;
void {
    opsCount += n;
}

这毫无意义。您可以在包含 CountOps.hpp 之前通过 #define COUNT_OPS 解决此问题，或者根本不费心尝试创建此函数。正确的路径取决于该库的使用方式。

我的意思不是要告诉您如何解决这个问题，而是希望能帮助您了解将来如何检测它，这样您就可以了解正在发生的事情以及为什么会发生，或者至少帮助其他试图提供帮助的人你。

最后一点:假设您的图像永远不会被看到。不仅某些用户看不到它们，而且将来搜索您的问题的其他用户也看不到它，因此它教训了其他人从您的问题中学习的能力。您的编译器将在某种程度上在文本中发出这些错误。您应该从那里复制粘贴。