Question

我无法解决围绕我的向量和字符串的这个问题。我已经创建了一个用于读取着色器（OpenGL）的类，但目前还没有在我的程序中的任何地方使用它。问题是当我测试我的应用程序时，我仍然会收到错误。我缩小错误的函数在下面，如果我注释掉行，我的应用程序按预期运行（与sProgram相关的未注释行会导致错误：

#define FOR(q, n) for (int q = 0; q < n; q++)
#define SFOR(q, s, e) for (int q = s; q <= e; q++)
#define RFOR(q, n) for (int q = n; q >= 0; q--)
#define RSFOR(q, s, e) for (int q = s; q >= e; q--)

#define ESZ(elem) (int)elem.size()
...
...
bool GLShader::LoadShader(string sFile, int a_iType)
{
    FILE* fp = fopen(sFile.c_str(), "rt");
    if (!fp)
      return false;

   // Get all lines from a file
   vector<string> sLines;    
   char sLine[255];
   while (fgets(sLine, 255, fp))
      sLines.push_back(sLine);
   fclose(fp);

  // const char** sProgram = new const char*[ESZ(sLines)]; <--- problem with sProgram
  // FOR(i, ESZ(sLines))sProgram[i] = sLines[i].c_str(); 

  uiShader = glCreateShader(a_iType);

 // glShaderSource(uiShader, ESZ(sLines), sProgram, NULL); 
  glCompileShader(uiShader);

 // delete[] sProgram; <--- Error

  int iCompilationStatus;
  glGetShaderiv(uiShader, GL_COMPILE_STATUS, &iCompilationStatus);

  if (iCompilationStatus == GL_FALSE)
    return false;

  iType = a_iType;
  bLoaded = true;

  return 1;
}

这是我收到的错误：

Error   1   error LNK2019: unresolved external symbol __imp___CrtDbgReportW 
referenced in function "public: class std::basic_string<char,struct
std::char_traits<char>,class std::allocator<char> > & __thiscall 
std::vector<class std::basic_string<char,struct std::char_traits<char>,
class std::allocator<char> >,class std::allocator<class 
std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > 
> >::operator[](unsigned int)" 
(??A?$vector@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@V?
$allocator@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std
@@@2@@std@@QAEAAV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@1@I@Z)
c:\Users\Me\documents\visual studio 2013\Projects\FooV1\FooV1\Bar.obj

在输出中：

1>------ Build started: Project: FooV1, Configuration: Debug Win32 ------
1>  main.cpp
1>Bar.obj : error LNK2019: unresolved external 
  symbol __imp___CrtDbgReportW referenced in function "public: class 
  std::basic_string<char,struct std::char_traits<char>,class 
  std::allocator<char> > & __thiscall std::vector<class 
  std::basic_string<char,struct std::char_traits<char>,class 
  std::allocator<char> >,class std::allocator<class 
  std::basic_string<char,struct std::char_traits<char>,class 
  std::allocator<char> > > >::operator[](unsigned int)" 
  (??A?$vector@V?$basic_string@DU?$char_traits@D@std@@V?$allocator
  @D@2@@std@@V?$allocator@V?$basic_string@DU?$char_traits@D@std@@V?
  $allocator@D@2@@std@@@2@@std@@QAEAAV?$basic_string@DU?$char_traits
  @D@std@@V?$allocator@D@2@@1@I@Z)
1>c:\users\Me\documents\visual studio 2013\Projects\FooV1\Debug\FooV1.exe : 
  fatal error LNK1120: 1 unresolved externals
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

Answer 1

glShaderSource并不一定非常复杂（它不依赖于每行指针而且我不确定如果你给它一个代码它会是你的代码行分为第255个字符）。将所有文本放入一个字符串或缓冲区，获取指向它的指针，并使用指向该指针的指针调用glShaderSource。

bool GLShader::LoadShader(string sFile, int a_iType)
{
    std::ifstream isSrc(sFile.c_str(), std::ifstream::in);
    if(!isSrc.good())
        return false;

    std::string sLines = "";
    std::string sLine;

    while (isSrc.good()) {
        std::getline(isSrc, sLine);
        sLines.append(sLine);
    }
    isSrc.close();

    uiShader = glCreateShader(a_iType);

    const char* szSrc = sLines.c_str();
    glShaderSource(uiShader, 1, &szSrc, NULL);

对于有趣和傻笑，使用内存映射文件的版本io。

bool GLShader::LoadShader(const std::string& sFile, int a_iType)
{
    bool success = false;

    // Windows implementation.
    HANDLE fileHandle = INVALID_HANDLE_VALUE, mappingHandle = INVALID_HANDLE_VALUE;

    do { // not actually a loop
        fileHandle = CreateFile(sFile.c_str(), FILE_GENERIC_READ, FILE_SHARE_READ, nullptr, OPEN_EXISTING, 0, nullptr);
        if (fileHandle == INVALID_HANDLE_VALUE)
            break;

        mappingHandle = CreateFileMapping(fileHandle, nullptr, PAGE_READONLY, 0, 0, nullptr);
        if (mappingHandle == INVALID_HANDLE_VALUE)
            break;

        LPVOID const lpvData = MapViewOfFileEx(mappingHandle, FILE_MAP_READ, 0, 0, 0, nullptr);
        if (!lpvData)
            break;

        /*
            ... other stuff
        */

        const char* pszSrc = static_cast<const char*>(lpvData);
        glShaderSource(uiShader, 1, &pszSrc, nullptr);

        /*
            ... the rest of your code
        */

        success = true;
    } while (false); // never repeat

            // cleanup
    if (mappingHandle != INVALID_HANDLE_VALUE)
        CloseHandle(mappingHandle);
    if (fileHandle != INVALID_HANDLE_VALUE)
        CloseHandle(fileHandle);

    return success;
}

未调用的函数会导致错误

1 个答案: