C is a general-purpose, procedural programming language that provides low-level access to system memory. It is known for its efficiency, portability, and power, making it ideal for system programming.
C Anti-Patterns Overview
C, despite being a foundational language with decades of use, has several common anti-patterns that can lead to bugs, security vulnerabilities, and maintenance problems. Here are the most important anti-patterns to avoid when writing C code.
Not Checking Return Values
Always check return values from functions that can fail, such as memory allocation, file operations, and network calls.
Buffer Overflows
Use bounded string functions and explicit buffer size management to prevent buffer overflows, which can lead to security vulnerabilities.
Memory Leaks
Always free allocated memory, even in error paths, to prevent memory leaks.
Using gets() Function
Never use gets()
as it has no bounds checking. Use fgets()
or other bounded input functions instead.
Integer Overflow
Be aware of integer overflow, especially when calculating sizes for memory allocation.
Using Uninitialized Variables
Always initialize variables before using them to avoid undefined behavior.
Not Using const for Read-Only Parameters
Use const
for function parameters that should not be modified to communicate intent and enable compiler optimizations.
Using Magic Numbers
Use named constants instead of magic numbers to improve code readability and maintainability.
Using Global Variables
Avoid global variables as they create hidden dependencies and make code harder to test and reason about.
Not Using Header Guards
Always use header guards to prevent multiple inclusion of header files, which can lead to compilation errors.
Using void* Without Type Checking
Avoid using void*
without proper type checking. Use tagged unions or other type-safe alternatives when possible.
Not Using Function Prototypes
Always use function prototypes to enable compiler type checking and avoid implicit declarations.
Not Checking for NULL After Memory Allocation
Always check if memory allocation functions like malloc
return NULL before using the allocated memory.
Using strcpy and strcat Unsafely
Avoid using unsafe string functions like strcpy
and strcat
. Use bounded alternatives like strncpy
and strncat
, or better yet, use safer string handling libraries.
Using Switch Statements Without Default Case
Always include a default case in switch statements to handle unexpected values.
Not Using Static Analysis Tools
Use static analysis tools and compiler warnings to catch common bugs and issues in your code.
Using Macros Instead of Inline Functions
Prefer inline functions over macros when possible, as they provide type checking and avoid common macro pitfalls.
Not Using Defensive Programming
Use defensive programming techniques to handle invalid inputs and edge cases.
Not Using Proper Error Codes
Use consistent, well-documented error codes or an error handling system to communicate failures.