Compiler Warning (level 1) C4218
Collapse the table of content
Expand the table of content
Important This document may not represent best practices for current development, links to downloads and other resources may no longer be valid. Current recommended version can be found here. ArchiveDisclaimer

Compiler Warning (level 1) C4218

Error Message

nonstandard extension used : must specify at least a storage class or a type

With the default Microsoft extensions (/Ze), you can declare a variable without specifying a type or storage class. The default type is int.


// C4218.c
// compile with: /W4
i;  // C4218

int main()

Such declarations are invalid under ANSI compatibility (/Za).

© 2015 Microsoft