In spite of the first rule (use Fortran) in the Starlink Application Programming Standard, SGP/16, there is a Starlink C Programming Standard -- SGP/4. Its general style and philosophy are very similar to the Fortran standard, though obviously many of the rules are only directly relevant to one of the languages.
The suggestions which it contains are made with maintainability, portability and efficiency in mind. Several of them are made because certain code constructs will have different effects in different C implementations. In some cases the ambiguity is resolved by the ANSI standard. However, it may be some time before all C implementations meet the standard, and in any case it is preferable to avoid code which suggests more than one possibility to the human reader.
ADAM The Starlink Software Environment