Compiler Warning C4959
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 C4959

Error Message

cannot define unmanaged struct 'type' in /clr:safe because accessing its members yields unverifiable code

Accessing a member of an unmanaged type will produce an unverifiable (peverify.exe) image.

For more information, see Pure and Verifiable Code.

This warning is issued as an error and can be disabled with the warning pragma or the /wd compiler option.

The following sample generates C4959:

// C4959.cpp
// compile with: /clr:safe

// Uncomment the following line to resolve.
// #pragma warning( disable : 4959 )
struct X {
   int data;

int main() {
   X x; = 10;   // C4959
© 2016 Microsoft