如何将 const char* API 导入 C#？
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How to import const char* API to C#?
提问by Mike Chess
Given this C API declaration how would it be imported to C#?
鉴于此 C API 声明，它将如何导入到 C#？
const char* _stdcall z4LLkGetKeySTD(void);
I've been able to get this far:
我已经能够做到这一点：
[DllImport("zip4_w32.dll",
CallingConvention = CallingConvention.StdCall,
EntryPoint = "z4LLkGetKeySTD",
ExactSpelling = false)]
private extern static const char* z4LLkGetKeySTD();
采纳答案by JaredPar
Try this
尝试这个
[DllImport("zip4_w32.dll",
CallingConvention = CallingConvention.StdCall,
EntryPoint = "z4LLkGetKeySTD",
ExactSpelling = false)]
private extern static IntPtr z4LLkGetKeySTD();
You can then convert the result to a String by using Marshal.PtrToStringAnsi(). You will still need to free the memory for the IntPtr using the appropriate Marshal.Free* method.
然后，您可以使用 Marshal.PtrToStringAnsi() 将结果转换为字符串。您仍然需要使用适当的 Marshal.Free* 方法为 IntPtr 释放内存。
回答by Cody Brocious
Just use 'string' instead of 'const char *'.
只需使用 'string' 而不是 'const char *'。
Edit: This is dangerous for the reason JaredPar explained. If you don't want a free, don't use this method.
编辑：由于 JaredPar 解释的原因，这很危险。如果您不想要免费，请不要使用此方法。
回答by Robert
Always use C++ const char* or char* and not std::string.
始终使用 C++ const char* 或 char* 而不是 std::string。
Also keep in mind that char in C++ is a sbyte in C# and unsigned char is a byte in C#.
还要记住，C++ 中的 char 是 C# 中的一个 sbyte，而 unsigned char 是 C# 中的一个字节。
It is advisable to use unsafe code when dealing with DllImport.
建议在处理 DllImport 时使用不安全的代码。
[DllImport("zip4_w32.dll",
CallingConvention = CallingConvention.StdCall,
EntryPoint = "z4LLkGetKeySTD",
ExactSpelling = false)]
private extern static sbyte* or byte* z4LLkGetKeySTD();
void foo()
{
string res = new string(z4LLkGetKeySTD());
}
