C++ 函数指针类型错误

Question

我需要使用以下函数，但我在参数方面遇到了麻烦:

在这种情况下，未设置 IP 地址。

cwbCO_SysHandle system;
LPSTR ipAddress = "";
ULONG ipLength = 32;
cwbCO_GetIPAddress(system, ipAddress, &ipLength);

我知道我需要将指针传递给 LPSTR 作为参数，但设置以下代码也不起作用:

cwbCO_SysHandle system;
LPSTR ipAddress = "";
ULONG ipLength = 32;
cwbCO_GetIPAddress(system, &ipAddress, &ipLength); //Incompatible types LPSTR* and LPSTR

正确的做法是什么？

语法

UINT CWB_ENTRY cwbCO_GetIPAddress(cwbCO_SysHandle 系统, LPSTR IPAddress, PULONG 长度);

参数

cwbCO_SysHandle系统-输入

Handle that previously was returned by cwbCO_CreateSystem or cwbCO_CreateSystemLike. It is the
IBM i identification.

LPSTR IP 地址 - 输出

Pointer to a buffer that will contain the NULL-terminated IP address in dotted-decimal notation (in
the form "nnn.nnn.nnn.nnn" where each "nnn" is in the range of from 0 to 255).

PULONG 长度 - 输入/输出

Pointer to the length of the IPAddress buffer. If the buffer is too small to hold the output, including
room for the terminating NULL, the size of the buffer

Answer 1

我找到了文档，cwbCO_GetIPAddress

这里的相关部分是(强调):

LPSTR IPAddress - output Pointer to a buffer that will contain the NULL-terminated IP address in dotted-decimal notation (in the form "nnn.nnn.nnn.nnn" where each "nnn" is in the range of from 0 to 255).

所以你的代码应该看起来更像这样:

cwbCO_SysHandle system;
char ipAddress[32]; //A buffer, not a pointer!
ULONG ipLength = 32;
cwbCO_GetIPAddress(system, ipAddress, &ipLength);

此外，请确保使用 cwbCO_CreateSystem 或 cwbCO_CreateSystemLike 初始化您的系统。