|  | llvm/lib/Support/Unix README | 
|  | =========================== | 
|  |  | 
|  | This directory provides implementations of the lib/System classes that | 
|  | are common to two or more variants of UNIX. For example, the directory | 
|  | structure underneath this directory could look like this: | 
|  |  | 
|  | Unix           - only code that is truly generic to all UNIX platforms | 
|  | Posix        - code that is specific to Posix variants of UNIX | 
|  | SUS          - code that is specific to the Single Unix Specification | 
|  | SysV         - code that is specific to System V variants of UNIX | 
|  |  | 
|  | As a rule, only those directories actually needing to be created should be | 
|  | created. Also, further subdirectories could be created to reflect versions of | 
|  | the various standards. For example, under SUS there could be v1, v2, and v3 | 
|  | subdirectories to reflect the three major versions of SUS. |