|  | The ground truth of standards | 
|  | ============================= | 
|  |  | 
|  | Like any modern libc, LLVM libc also supports a wide number of standards and | 
|  | extensions. To avoid developing headers, wrappers and sources in a disjointed | 
|  | fashion, LLVM libc employs ground truth files. These files live under the | 
|  | ``spec`` directory and list ground truth corresponding the ISO C standard, the | 
|  | POSIX extension standard, etc. For example, the path to the ground truth file | 
|  | for the ISO C standard is ``spec/stdc.td``. Tools like the header generator | 
|  | (described in the header generation document), docs generator, etc. use the | 
|  | ground truth files to generate headers, docs etc. |