Global scope and storage

• There MUST be at most five exported functions per source file.
• There SHOULD be only one non-function exported symbol per source file.

  Rationale: when statically linking executables against libraries, most linker algorithms operate with object file granularity, not symbol granularity. With only one exported symbol per source file, the link process has the finest granularity. Hint: track exported symbols with nm.

• There SHOULD NOT be any unused local (tagged with static) functions in source files. Hint: hunt unused functions with gcc -Wunused.
• In order to block known abuses of the previous rules, there MUST NOT appear more than ten functions (exported + local) per source file.
• Static declarations are NOT RECOMMENDED. When required by a particular circumstance, there MUST be only one static variable per line.
• When initializing a static array or structure with const elements, the initializer value MUST start on the line after the declaration:

  This is wrong: static int primes[] = { 2, 3, 5, 7, 11 };

  
  These are correct:

            
  
            static const int primes[] =
            {
               2, 3, 5, 7, 11
            };
            
            static const struct
            {
              char		c;
              void		(*handler)(void *);
            }		handlers[] =
            {
              { 'h', &left_handler },
              { 'j', &up_handler },
              { 'k', &down_handler },
              { 'l', &right_handler },
              { '\0', 0 }
            };