Compiler Warning (level 1) C4627
'header_file': skipped when looking for precompiled header use
If the current source file has the /Yu (Use precompiled header file) option set, then the compiler ignores everything in the file before the precompiled header is included. Warning C4627 is generated in Visual Studio 2015 and earlier versions if header_file is included before the precompiled header file, and if the precompiled header does not also include header_file.
Example
This sample demonstrates how the error can occur, and shows how to fix it:
// c4627.cpp
#include <iostream> // C4627 - iostream not included by pch.h
#include "pch.h" // precompiled header file that does not include iostream
// #include <iostream> // To fix, move the iostream header include here from above
int main()
{
std::cout << "std::cout is defined!\n";
}