In programming, what typically indicates a syntax error in a code snippet?

A syntax error in programming arises when the code is written in a way that does not conform to the rules of the programming language. This means the structure of the code is incorrect, and the interpreter or compiler cannot understand it.

When a syntax error occurs, the compiler or interpreter is responsible for providing feedback in the form of specific error messages. These messages indicate where the issue lies in the code, which helps the programmer identify and correct the mistake. Syntax errors typically prevent the program from running entirely, as the code must first be error-free in its structure before it can be executed.

The other options do not accurately represent indicators of syntax errors. Performance issues like running slower than expected can be due to logical errors or inefficient algorithms rather than syntax problems. Similarly, having incorrect output can stem from logical errors in the code, but it does not inherently indicate a syntax error. Therefore, the presence of specific error messages from the compiler is the most direct and clear indicator of a syntax error.