I'm writing some code for a game, and I'm attempting to write a helper function to return a string inside an object:
const char* getGhostName(GhostAI* ghostAI)
{
if (ghostAI) {
GhostInfo* ghostInfo = getGhostInfo(ghostAI);
const auto ghostName = ghostInfo->fields.u0A6Du0A67u0A74u0A71u0A71u0A66u0A65u0A68u0A74u0A6Au0A6F.u0A65u0A66u0A6Eu0A67u0A69u0A74u0A69u0A65u0A74u0A6Fu0A67;
const char* name = il2cppi_to_string(ghostName).c_str();
return name;
}
return "UNKNOWN";
}
And here is the il2cppi_to_string
functions:
std::string il2cppi_to_string(Il2CppString* str) {
std::u16string u16(reinterpret_cast<const char16_t*>(str->chars));
return std::wstring_convert<std::codecvt_utf8_utf16<char16_t>, char16_t>{}.to_bytes(u16);
}
std::string il2cppi_to_string(app::String* str) {
return il2cppi_to_string(reinterpret_cast<Il2CppString*>(str));
}
When I call getGhostName
, I end up with an empty string. Now I did get a warning from ReSharper which says:
Object backing the pointer will be destroyed at the end of the full-expression.
This is appearing on the following line inside getGhostName
when calling il2cppi_to_string
:
const char* name = il2cppi_to_string(ghostName).c_str();
I'm not entirely sure what this means or how I can modify the code to fix it. I absolutely hate working with strings in C .
CodePudding user response:
il2cppi_to_string()
returns a temporary std::string
, which will be destroyed at the end of the expression that calls il2cppi_to_string()
. You are obtaining a const char*
pointer to the data of that temporary std::string
, which is what ReSharper is warning you about. Since the temporary std::string
is destroyed before the return
, that means getGhostName()
is returning a dangling pointer to invalid memory.
To fix this, change getGhostName()
to return a std::string
instead of a const char*
:
std::string getGhostName(GhostAI* ghostAI)
{
if (ghostAI) {
GhostInfo* ghostInfo = getGhostInfo(ghostAI);
const auto ghostName = ghostInfo->fields.u0A6Du0A67u0A74u0A71u0A71u0A66u0A65u0A68u0A74u0A6Au0A6F.u0A65u0A66u0A6Eu0A67u0A69u0A74u0A69u0A65u0A74u0A6Fu0A67;
return il2cppi_to_string(ghostName);
}
return "UNKNOWN";
}