How to Use an Array of void* Function Pointers with Arbitrary Arguments in C

Learn how to safely manage an array of function pointers with different argument types in C using a common void pointer and structs for argument passing. --- This video is based on the question https://stackoverflow.com/q/79479091/ asked by the user 'DAVID KING DKTV' ( https://stackoverflow.com/u/13000191/ ) and on the answer https://stackoverflow.com/a/79479729/ provided by the user 'dbush' ( https://stackoverflow.com/u/1687119/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions. Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: How to create an array of pointers to functions with arbitrary arguments? Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l... The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license. If anything seems off to you, please feel free to drop me a comment under this video. --- The Challenge of Function Pointers with Arbitrary Arguments in C In C, you cannot directly create an array of function pointers if these functions have different argument lists. C requires that functions in the same pointer array share the same signature for proper type checking and calling. However, you might want to store pointers to multiple functions that take different parameter types and counts but share the same return type — for example, void. Why a Single void* Argument Is the Practical Solution The typical workaround is to define your functions to take a single void* argument. This allows you to store their pointers in an array of void (*)(void*) functions. Each function then casts the void* argument to the expected struct type containing its parameters. This method: Avoids unsafe, manual memory copying with memcpy Keeps function signatures compatible for the pointer array Enables passing rich and safe argument data through structured types Implementing the Safe Struct-based Approach Instead of packing raw bytes manually, define structs encapsulating each function's parameters: [[See Video to Reveal this Text or Code Snippet]] Benefits of Using Structs: Type Safety: You avoid unsafe byte manipulations and ensure each function receives the exact data it expects. Clarity: Functions clearly document their expected arguments in one place. Maintainability: Adding or changing function parameters involves simple struct adjustments. Summary While C doesn't support heterogeneous function pointer arrays with arbitrary arguments directly, using a unified function signature with a single void* argument combined with argument structs is the clearest and safest idiomatic approach. This technique balances flexibility and maintainability without sacrificing type safety as much as raw memcpy approaches. By embracing this pattern, your code remains clean, understandable, and safer from common pointer and memory errors.