我在不同的 .cpp 文件之间声明公共/外部结构对象时遇到问题。我正在尝试使用 imgui 记录器从挂钩记录一些消息。
该程序将崩溃ExampleAppLog my_log2; -> ImGuiTextBuffer Buf; -> class ImVector -> if (Data)
因为我ExampleAppLog* my_log2 = new ExampleAppLog();在一个包含 .h 的 .cpp 中执行此操作，其中包含 struct ExampleAppLog 以及 my_log2 的声明。
崩溃的相关代码 -> .h
struct ExampleAppLog
{
ImGuiTextBuffer Buf;
}
extern ExampleAppLog* my_log2;
.cpp
#include ".h"
ExampleAppLog* my_log2 = new ExampleAppLog(); //this line make it crash
imgui.h
struct ImGuiTextBuffer
{
ImVector<char> Buf;
}
class ImVector
{
public:
int Size;
int Capacity;
T* Data;
typedef T value_type;
typedef value_type* iterator;
typedef const value_type* const_iterator;
ImVector() { Size = Capacity = 0; Data = NULL; }
~ImVector() { if (Data) ImGui::MemFree(Data); }
inline bool empty() const { return Size == 0; }
inline int size() const { return Size; }
inline int capacity() const { return Capacity; }
inline value_type& operator[](int i) { IM_ASSERT(i < Size); return Data[i]; }
inline const value_type& operator[](int i) const { IM_ASSERT(i < Size); return Data[i]; }
inline void clear() { if (Data) { Size = Capacity = 0; ImGui::MemFree(Data); Data = NULL; } }
inline iterator begin() { return Data; }
inline const_iterator begin() const { return Data; }
inline iterator end() { return Data + Size; }
inline const_iterator end() const { return Data + Size; }
inline value_type& front() { IM_ASSERT(Size > 0); return Data[0]; }
inline const value_type& front() const { IM_ASSERT(Size > 0); return Data[0]; }
inline value_type& back() { IM_ASSERT(Size > 0); return Data[Size-1]; }
inline const value_type& back() const { IM_ASSERT(Size > 0); return Data[Size-1]; }
inline void swap(ImVector<T>& rhs) { int rhs_size = rhs.Size; rhs.Size = Size; Size = rhs_size; int rhs_cap = rhs.Capacity; rhs.Capacity = Capacity; Capacity = rhs_cap; value_type* rhs_data = rhs.Data; rhs.Data = Data; Data = rhs_data; }
inline int _grow_capacity(int size) const { int new_capacity = Capacity ? (Capacity + Capacity/2) : 8; return new_capacity > size ? new_capacity : size; }
inline void resize(int new_size) { if (new_size > Capacity) reserve(_grow_capacity(new_size)); Size = new_size; }
inline void resize(int new_size, const T& v){ if (new_size > Capacity) reserve(_grow_capacity(new_size)); if (new_size > Size) for (int n = Size; n < new_size; n++) Data[n] = v; Size = new_size; }
inline void reserve(int new_capacity)
{
if (new_capacity <= Capacity) return;
T* new_data = (value_type*)ImGui::MemAlloc((size_t)new_capacity * sizeof(T));
if (Data) //here is the crash. Data is 0x000000000 when crashing
memcpy(new_data, Data, (size_t)Size * sizeof(T));
ImGui::MemFree(Data);
};
示例代码 -> .h
struct ExampleAppLog
{
ImGuiTextBuffer Buf;
ImGuiTextFilter Filter;
ImVector<int> LineOffsets; // Index to lines offset
bool ScrollToBottom;
void Clear() { Buf.clear(); LineOffsets.clear(); }
void AddLog(const char* fmt, ...) IM_FMTARGS(2)
{
int old_size = Buf.size();
va_list args;
va_start(args, fmt);
Buf.appendv(fmt, args);
va_end(args);
for (int new_size = Buf.size(); old_size < new_size; old_size++)
if (Buf[old_size] == '\n')
LineOffsets.push_back(old_size);
ScrollToBottom = true;
}
void Draw(const char* title, bool* p_open = NULL)
{
ImGui::SetNextWindowSize(ImVec2(500, 400), ImGuiCond_FirstUseEver);
ImGui::Begin(title, p_open);
if (ImGui::Button("Clear")) Clear();
ImGui::SameLine();
bool copy = ImGui::Button("Copy");
ImGui::SameLine();
Filter.Draw("Filter", -100.0f);
ImGui::Separator();
ImGui::BeginChild("scrolling", ImVec2(0, 0), false, ImGuiWindowFlags_HorizontalScrollbar);
if (copy) ImGui::LogToClipboard();
if (Filter.IsActive())
{
const char* buf_begin = Buf.begin();
const char* line = buf_begin;
for (int line_no = 0; line != NULL; line_no++)
{
const char* line_end = (line_no < LineOffsets.Size) ? buf_begin + LineOffsets[line_no] : NULL;
if (Filter.PassFilter(line, line_end))
ImGui::TextUnformatted(line, line_end);
line = line_end && line_end[1] ? line_end + 1 : NULL;
}
}
else
{
ImGui::TextUnformatted(Buf.begin());
}
if (ScrollToBottom)
ImGui::SetScrollHere(1.0f);
ScrollToBottom = false;
ImGui::EndChild();
ImGui::End();
}
};
extern ExampleAppLog* my_log2;
一.cpp
#include ".h"
ExampleAppLog* my_log2 = new ExampleAppLog(); //this line make it crash
void LogHook(const char* Info)
{
my_log2->AddLog(Info);
}
二.cpp
#include ".h"
bool bDraw = true;
void Draw()
{
my_log2->Draw("Logger", &bDraw);
}
我尝试了许多不同的方法，但没有运气，但在尝试在多个 .cpp 中共享外部对象时不会崩溃。
记录器文档。
static ExampleAppLog my_log; //have tryd this but with extern etc. It still crash at the same place whan trying to share it globaly. If i do it all in one .cpp out sharing it publicly the code work
[...]
my_log.AddLog("Hello %d world\n", 123);
[...]
my_log.Draw("title");