error: expected unqualified-id before ‘{’ token on Linux gcc

Question

我在 linux 上使用 gcc (GCC) 7.3.1 20180303 (Red Hat 7.3.1-5) 编译以下代码时收到以下错误消息]没有问题。

...
#include "DDImage/NoIop.h"
static const char* const CLASS = "RemoveChannels";

// -------------------- Header -------------------- \ 
class RemoveChannels : public NoIop
{
public:
  //! Default constructor.
  RemoveChannels (Node* node) : NoIop(node)
  {
    this->_message = "\w+";
    this->operation = 1;
  }
  
  //! Virtual destructor.
  virtual ~RemoveChannels () {}
  
  void _validate(bool) override;

private: 
  //! Information private for the node.
  ChannelSet channels;
  std::regex rgx;
  const char* _message;
  int operation; // 0 = remove, 1 = keep
};

void RemoveChannels::_validate(bool for_real)
{
  if (!this->_message) // Fast return if you don't have anything in there.
  {
      set_out_channels(Mask_None); // Tell Nuke we didn't touch anything.
      return;
  }
  ...
  
}

...

在使用 gcc 编译上述代码时，我在 linux 上收到以下错误消息（在 windows 上它工作正常！）。

编译器错误：

RemoveChannels.cpp:28:1: error: expected unqualified-id before ‘{’ token
 {
 ^
RemoveChannels.cpp:65:6: error: ‘RemoveChannels’ has not been declared
 void RemoveChannels::_validate(bool for_real)
      ^~~~~~~~~~~~~~
/RemoveChannels.cpp: In function ‘void _validate(bool)’:
RemoveChannels.cpp:67:8: error: invalid use of ‘this’ in non-member function
   if (!this->_message) // Fast return if you don't have anything in there.
        ^~~~
...

如果我从实现函数中删除 this-> 并只使用 _message，它可以毫无问题地编译和工作。

任何人都可以向我解释为什么会发生这种情况，并且只发生在 linux 而不是发生在 windows 上吗？

Answer 1

简单示例

// -------------------- Header --------------------\
class RemoveChannels
{
public:
  int operation = 0;
};

int main ()
{
    RemoveChannels r;
    r.operation++;
}

当一行以反斜杠结束时，它会在下一行继续。这意味着 class RemoveChannels 被不小心注释掉了，一行注释泄漏到下一行。

解决方案：删除反斜杠

// -------------------- Header --------------------
class RemoveChannels
{
public:
  int operation = 0;
};

int main ()
{
    RemoveChannels r;
    r.operation++;
}

error: expected unqualified-id before ‘{’ token on Linux gcc

error: expected unqualified-id before ‘{’ token on Linux gcc

c++

gcc