未解析的外部符号，C++，VS 2015

Question

我已经阅读了 model answer on unresolved externals 并发现它非常有用，并且将其归结为最后两个我无法理解的顽固错误。

为了以防万一，我附上了所有代码，如果您想查看 headers 或其他任何内容，请说。

// Stokes theory calculations

#include <math.h>
#include <stdio.h>
#include <process.h>
#include <string.h>
#include <conio.h>
#include <stdlib.h>
#define ANSI
#include "../Allocation.h"

#define Main
#define Char    char
#define Int     int
#define Double  double
#include "../Allocation.h"
#include "../Headers.h"


Double
kH, skd, ckd, tkd, SU;
Double
ss[6], t[6], C[6], D[6], E[6], e[6];

// Main program

int main(void)
{
    int i, Read_data(void), iter, Iter_limit = 40;

    double  F(double), kd1, kd2, kFM, omega, delta, accuracy = 1.e-6, F1, F2, Fd;
    void    CDE(double), AB(void), Output(void);

    Input1 = fopen("../Data.dat", "r");
    strcpy(Convergence_file, "../Convergence.dat");
    strcpy(Points_file, "../Points.dat");
    monitor = stdout;
    strcpy(Theory, "Stokes");
    strcpy(Diagname, "../Catalogue.res");

    Read_data();

    z = dvector(0, 2 * n + 10);
    Y = dvector(0, n);
    B = dvector(0, n);
    coeff = dvector(0, n);
    Tanh = dvector(0, n);

    monitor = stdout;

    H = MaxH;

    iff(Case, Wavelength)
    {
        kd = 2. * pi / L;
        kH = kd * H;
        CDE(kd);
    }

    // If period is specified, solve dispersion relation using secant method

    // Until February 2015 the bisection method was used for this.
    // I found that in an extreme case (large current) the bracketting
    // of the solution was not correct, and the program failed,
    // without printing out a proper error message.

    iff(Case, Period)
    {
        fprintf(monitor, "\n# Period has been specified.\n# Now solving for L/d         iteratively, printing to check convergence\n\n");
        omega = 2 * pi / T;
        // Fenton & McKee for initial estimate
        kFM = omega*omega*pow(1 / tanh(pow(omega, 1.5)), (2. / 3.));
        kd1 = kFM;
        kd2 = kFM*1.01;
        CDE(kd2);
        F2 = F(kd2);
        for (iter = 1; iter <= Iter_limit; ++iter)
        {
            CDE(kd1);
            F1 = F(kd1);
            Fd = (F2 - F1) / (kd2 - kd1);
            delta = F1 / Fd;
            kd2 = kd1;
            kd1 = kd1 - delta;
            fprintf(monitor, "%8.4f\n", 2 * pi / kd1);
            if (fabs(delta / kd1) < accuracy) break;
            F2 = F1;
            if (iter >= Iter_limit)
            {
                printf("\n\nSecant for solution of wavenumber has not converged");
                printf("\nContact John Fenton johndfenton@gmail.com");
                getch();
                exit(1);
            }
        }
        kd = kd1;
        kH = kd * H;
    }

    z[1] = kd;
    z[2] = kH;

    SU = 0.5*kH / pow(kd, 3);
    printf("\n# Stokes-Ursell no.: %7.3f", SU);
    if (SU > 0.5)
        printf(" > 1/2. Results are unreliable");
    else
        printf(" < 1/2, Stokes theory should be valid");

    e[1] = 0.5 * kH;
    for (i = 2; i <= n; i++) e[i] = e[i - 1] * e[1];

    // Calculate coefficients

    AB();

    z[7] = C[0] + e[2] * C[2] + e[4] * C[4]; // ubar
    z[8] = -e[2] * D[2] - e[4] * D[4];
    z[9] = 0.5 * C[0] * C[0] + e[2] * E[2] + e[4] * E[4];

    if (Current_criterion == 1)
    {
        z[5] = Current*sqrt(kd);
        z[4] = z[7] + z[5];
        z[6] = z[4] + z[8] / kd - z[7];
    }

    if (Current_criterion == 2)
    {
        z[6] = Current*sqrt(kd);
        z[4] = z[6] - z[8] / kd + z[7];
        z[5] = z[4] - z[7];
    }

    iff(Case, Wavelength) z[3] = 2 * pi / z[4];
    iff(Case, Period) z[3] = T * sqrt(kd);

    for (i = 1; i <= n; i++)
        Tanh[i] = tanh(i*z[1]);

    //  Output results and picture of wave

    Solution = fopen("Solution.res", "w");
    Elevation = fopen("Surface.res", "w");
    Flowfield = fopen("Flowfield.res", "w");

    Output();

    fflush(NULL);
    printf("\nTouch key to continue "); getch();
    printf("\n\nFinished\n");
}

我收到这些错误消息：

LNK2019 unresolved external symbol "void __cdecl Output(void)" (?Output@@YAXXZ) referenced in function _main Stokes

LNK2019 unresolved external symbol "double * __cdecl dvector(long,long)" (?dvector@@YAPANJJ@Z) referenced in function _main Stokes

我已经检查了列表中的所有内容，试图找出这些错误的来源，并将其减少到只剩下这两个。

到目前为止尝试过的事情：

检查基本语法
检查并确保正确 headers 可用
查看了外部依赖项（但我真的不知道我在这里做什么）
查看了已尝试 here 但 none 有效的解决方案。

如有任何帮助，我们将不胜感激！

Answer 1

Unresolved External Symbols 意味着您的代码无法找到您尝试使用的方法或 class 的定义。这通常意味着发生了一件（或多件）事情：

您没有指向包含您正在使用的库的对象库（.lib Windows，.so Linux）的目录
您忘记在 linker 中指定您需要使用有问题的库（kernel32.lib、user32.lib、...的列表需要包含名称您正在使用的图书馆）
您尝试使用的库应该静态 link 编辑，而您正尝试动态 link 它（反之亦然）。检查图书馆的文档并确保您使用的是正确的表格。一些库希望包含或省略额外的 #define 语句，具体取决于您是 link 静态还是动态。
您更改了构建选项而忘记更新其他构建选项中的库。如果您设置为 Release 或 x64，请检查以确保您的构建选项在所有环境中都设置正确。

编辑： 我还将证实其他人在原始评论线程中所说的话：确保定义 Output() 和 dvector() 的代码是 link被你的代码访问了。

还有一些其他选项，但那些是最常出现的大选项。

未解析的外部符号，C++，VS 2015

Unresolved External symbol, C++, VS 2015

c++

unresolved-external