Does C++ support Variable Length Arrays?

c++ c++11 variable-length-array
Lightness Races in Orbit picture Lightness Races in Orbit · Dec 21, 2011 · Viewed 18.3k times · Source

No, wait, bear with me...

VLAs were always a GCC extension, but they were adopted by C99:

[C99: 6.7.5.2/4]: If the size is not present, the array type is an incomplete type. If the size is * instead of being an expression, the array type is a variable length array type of unspecified size, which can only be used in declarations with function prototype scope; such arrays are nonetheless complete types. If the size is an integer constant expression and the element type has a known constant size, the array type is not a variable length array type; otherwise, the array type is a variable length array type.

C99 is also known as ISO/IEC 9899:1999.

Now:

[C++11: 1.1/2]: C++ is a general purpose programming language based on the C programming language as specified in ISO/IEC 9899:1999 (hereinafter referred to as the C standard). In addition to the facilities provided by C, C++ provides additional data types, classes, templates, exceptions, namespaces, operator overloading, function name overloading, references, free store management operators, and additional library facilities.

So shouldn't C++11 have VLAs too?

Answer

Johannes Schaub - litb picture Johannes Schaub - litb · Dec 21, 2011

That leeway wording doesn't mean that any and everything in C99 is in C++11. What you quoted is just introductory text.

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