---
description: "Learn more about: Compiler Limits"
title: "Compiler Limits"
ms.date: "06/05/2023"
helpviewer_keywords: ["cl.exe compiler, limits for language constructs"]
---
# Compiler Limits

The C++ standard recommends limits for various language constructs. The following is a list of cases where the Microsoft C++ compiler does not implement the recommended limits. The first number is the limit that is established in the ISO C++ 11 standard (INCITS/ISO/IEC 14882-2011[2012], Annex B) and the second number is the limit implemented by the Microsoft C++ compiler:

- Nesting levels of compound statements, iteration control structures, and selection control structures - C++ standard: 256, Microsoft C++ compiler: depends on the combination of statements that are nested, but generally between 100 and 110.

- Parameters in one macro definition - C++ standard: 256, Microsoft C++ compiler using `/Zc:preprocessor-`:127 or using `/Zc:preprocessor`:32767.

- Arguments in one macro invocation - C++ standard: 256, Microsoft C++ compiler using `/Zc:preprocessor-`:127 or using `/Zc:preprocessor`:32767.

- Characters in a character string literal or wide string literal (after concatenation) - C++ standard: 65536, Microsoft C++ compiler: 65535 single-byte characters, including the NULL terminator, and 32767 double-byte characters, including the NULL terminator.

- Levels of nested class, structure, or union definitions in a single `struct-declaration-list` - C++ standard: 256, Microsoft C++ compiler: 16.

- Member initializers in a constructor definition - C++ standard: 6144, Microsoft C++ compiler: at least 6144.

- Scope qualifications of one identifier - C++ standard: 256, Microsoft C++ compiler: 127.

- Nested **`extern`** specifications - C++ standard: 1024, Microsoft C++ compiler: 9 (not counting the implicit **`extern`** specification in global scope, or 10, if you count the implicit **`extern`** specification in global scope..

- Template arguments in a template declaration - C++ standard: 1024, Microsoft C++ compiler: 2046.

## See also

[Nonstandard Behavior](../cpp/nonstandard-behavior.md)