By Savi Jagga. Reflection is a mechanism in programming to implement generic code that can work for all types of objects. It helps recognizing the format for the objects at runtime and invoke the methods of that object and access the fields of these objects. This is used in various tasks such as invocation or remote method where a descriptor for that particular class is returned providing information about its class, variables and methods.
Using these descriptors itself one can easily invoke instance methods and access their variables. In above syntax of a class describing a class descriptor various flags have been used in the macros defined for the class. Are you looking for something like this?
GNU lightning - Wikipedia, the free encyclopedia To be clear, it sounds like you're looking for just-in-time compilation, not reflection. I would argue that reflection is quite possible in C, albeit, crudely. Use function pointers, and if need be, a lookup list, and viola, reflection. Replies: 5 Last Post: , AM. Replies: 23 Last Post: , PM. Replies: 1 Last Post: , PM. Two basic questions about reflection By George2 in forum C Programming.
Replies: 0 Last Post: , PM. AceUnit is a unit test framework for C that does exactly this. Combining parsing and the linker to generate symbol arrays can give very nice results - if your environment is so much under your control that you can ensure that working with the linker that way works for you. And of course you can combine all approaches to stitch together the bits and pieces until they fit your needs.
You would need to implement it from yourself from the ground up. In straight C, there is no runtime information whatsoever kept on structure and composite types. Metadata simply does not exist in the standard. For similar reasons to the author of the question, I have been working on a C-type-reflection-API along with a C reflection graph database format and a clang plug-in that writes reflection metadata.
The Crefl API provides runtime access to reflection metadata for C structure declarations with support for arbitrarily nested combinations of: intrinsic, set, enum, struct, union, field member , array, constant, variable.
A C reflection API provides access to runtime reflection metadata for C structure declarations with support for arbitrarily nested combinations of: intrinsic, set, enum, struct, union, field, array, constant, variable. The library is still a work in progress. The hope is to find others who are interested in reflection support in C. Parsers and Debug Symbols are great ideas. However, the gotcha is that C does not really have arrays.
Just pointers to stuff. This is a problem for human readers let alone any automated tool. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Reflection support in C Ask Question. Asked 12 years, 2 months ago. Active 8 months ago. Viewed 23k times. I know it is not supported, but I am wondering if there are any tricks around it.
Any tips? Improve this question. It is contrary to their philosophy of "you don't pay for what you don't use. See other answers. The thing I am trying to do is find what the parameters for a function before calling dlsym 3. Thanks for the answers — adk. C won't do this. You have to step outside the C language. This is practical. Implementing basic COM interfaces could bring a little reflection into your code.
Add a comment. Active Oldest Votes. What is needed is a tool that: Parses language source text Builds abstract syntax trees representing every detail of the program. It is helpful if the ASTs retain comments and other details of the source code layout such as column numbers, literal radix values, etc.
Moreover, you can get the type from an existing object and access its properties. When you use attributes in your code, reflection gives you access as it provides objects of Type that describe modules, assemblies, and types. To understand reflection, there are a few basics you should understand about modules, types, and members:. You need to use Reflection when you want to inspect the contents of an assembly. A program reflects on itself when it extracts metadata from its assemblies, then uses it to modify its own behavior or inform the user.
Reflection can be used to create applications called type browsers which allow users to select types and then read the data provided about them. This example illustrates how to use the static method GetType to find the Type of a variable:. Implementing reflection in C requires a two-step process. To access the sample class Calculator from Test. And access its members the following examples illustrate getting values for the public double Number property :.
The main class for reflection is the System.
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