(Command-line option to suppress warning: -w-pch) 

This warning is issued when pre-compiled headers are enabled but the compiler could not generate one, for one of the following reasons: 

ReasonExplanation 

write failedThe compiler could not write to the pre-compiled header file. This occurs if you specified an invalid location to cache precompiled headers or if the disk is full. 

code in headerOne of the headers contained a non-inline function body. 

initialized data in headerOne of the headers contained a global variable definition (in C, a global variable with an initializer; in C++ any variable not declared as 'extern'). 

header incompleteThe pre-compiled header ended in the middle of a declaration, for example, inside a class definition (this often happens when there is a missing closing brace in a header file).