Language 1
The Language 1 options determine which programming language to use and which extensions to enable.

For more information about the supported languages, their dialects, and their extensions, see Using C and Using C++.
Language conformance
Controls how strictly the compiler adheres to the standard C or C++ language. Choose between:
C dialect
Selects the dialect if C is the supported language. Choose between:
- Standard C
Enables the C18 standard, also known as Standard C. This is the default standard used in the compiler, and it is stricter than C89. Features specific to C89 cannot be used. In addition, choose between:
Allow VLA, allows the use of C11 variable length arrays.
C++ inline semantics, enables C++ inline semantics when compiling a Standard C source code file.
- Require prototypes
Forces the compiler to verify that all functions have proper prototypes, which means that source code containing any of the following will generate an error:
A function call of a function with no declaration, or with a Kernighan & Ritchie C declaration.
A function definition of a public function with no previous prototype declaration.
An indirect function call through a function pointer with a type that does not include a prototype.