[英]Undeclared Identifier Error when using function returning pointers to functions (C++ on Visual Studio)
[英]Undeclared identifier, when defining macro to load vulkan function pointers
我正在尝试使用 cmake 启动并运行 vulkan。 我目前正在尝试使用此示例动态加载 vulkan 函数指针
在这里,他们使用宏的构造来更轻松地从 vulkan 加载器加载所有函数指针。
现在我在以这种特定方式加载指针时遇到了一些问题,我得到 3 个可能密切相关的错误:
error C2065: 'vkGetInstanceProcAddr': undeclared identifier
error C2065: 'PFN_vkGetInstanceProcAddr': undeclared identifier
error C2146: syntax error: missing ';' before identifier 'GetProcAddress'
全部抛出 list_vulkan_functions.inl(5,1)
我觉得很奇怪,在这个例子中,他们没有在 list_vulkan_functions.inl 中包含任何文件,所以在我看来它抛出“未声明标识符”的错误似乎是合乎逻辑的,这怎么可能工作? 我已经看到了这种方法的多个例子,所以我一定是做错了什么,但我似乎无法弄清楚是什么。
list_vulkan_functions.inl
#ifndef EXPORTED_VULKAN_FUNCTION
#define EXPORTED_VULKAN_FUNCTION( function )
#endif
EXPORTED_VULKAN_FUNCTION( vkGetInstanceProcAddr ) // <--error gets thrown here
#undef EXPORTED_VULKAN_FUNCTION
此文件随后包含在以下文件中: vulkan_functions.h
#ifndef VULKAN_FUNCTIONS_H_
#define VULKAN_FUNCTIONS_H_
#include "vulkan.h"
namespace vulkan_test
{
#define EXPORTED_VULKAN_FUNCTION(name) extern PFN_##name name;
#define GLOBAL_LEVEL_VULKAN_FUNCTION(name) extern PFN_##name name;
#define INSTANCE_LEVEL_VULKAN_FUNCTION(name) extern PFN_##name name;
#define INSTANCE_LEVEL_VULKAN_FUNCTION_FROM_EXTENSION(name, extension) extern PFN_##name name;
#define DEVICE_LEVEL_VULKAN_FUNCTION(name) extern PFN_##name name;
#define DEVICE_LEVEL_VULKAN_FUNCTION_FROM_EXTENSION(name, extension) extern PFN_##name name;
#include "list_vulkan_functions.inl"
} // namespace vulkan_test
#endif
vulkan_functions.cpp
#include "vulkan_functions.h"
namespace vulkan_test
{
#define EXPORTED_VULKAN_FUNCTION(name) PFN_##name name;
#define GLOBAL_LEVEL_VULKAN_FUNCTION(name) PFN_##name name;
#define INSTANCE_LEVEL_VULKAN_FUNCTION(name) PFN_##name name;
#define INSTANCE_LEVEL_VULKAN_FUNCTION_FROM_EXTENSION(name, extension) PFN_##name name;
#define DEVICE_LEVEL_VULKAN_FUNCTION(name) PFN_##name name;
#define DEVICE_LEVEL_VULKAN_FUNCTION_FROM_EXTENSION(name, extension) PFN_##name name;
#include "list_vulkan_functions.inl"
} // namespace vulkan_test
和vulkan_library.cpp
bool vulkan_test::load_vulkan_function(LIBRARY_TYPE const& vulkanLibrary)
{
#define EXPORTED_VULKAN_FUNCTION(name) \
name = (PFN_##name)LOAD_FUNCTION(vulkanLibrary, #name); \
if (name == nullptr) \
{ \
std::cout << "Could not load exported Vulkan function named: " #name << "\n"; \
return false; \
}
#include "list_vulkan_functions.inl"
return true;
}
确保您的load_vulkan_function
函数在vulkan_test
命名空间中声明,并且vulkan_functions.h
包含在vulkan_library.cpp
。
这里的关键是您必须将LOAD_FUNCTION
的结果分配给在vulkan_test
命名空间中声明的extern
变量name
(基本上是vulkan_test::vkGetInstanceProcAddr
)(请参阅vulkan_functions.h#8
- 或英特尔的来源):
vulkan_library.cpp
#include "vulkan_functions.h"
...
bool vulkan_test::load_vulkan_function(LIBRARY_TYPE const& vulkanLibrary)
{
#define EXPORTED_VULKAN_FUNCTION(name) \
vulkan_test::name = (PFN_##name)LOAD_FUNCTION(vulkanLibrary, #name); \
if (vulkan_test::name == nullptr) \
...
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