Structures variables and declarations

Alignment

• Declared identifiers MUST be aligned with the function name, using tabulations only. Hint: Emacs users, use M-I.

  The following is wrong: int foo() { int i = 0; return i; }

  The following is correct:

            
  
            int     foo()
            {
              int   i = 0;
            
              return i;
            }
            
            

  
  
• In C, pointerness is not part of the type. Therefore, the pointer symbol (*) in declarations MUST appear next to the variable name, not next to the type.

  The following is incorrect (and probably does not have the intended meaning): const char* str1, str2;

  The following is correct:

            
  
            const char   *str1;
            const char   *str2;
            
            

  
  
• Structure and union fields MUST be aligned with the type name, using tabulations.
• When declaring a structure or an union, there MUST be only one field declaration per line.

  This is incorrect: struct s_point { int x, y; long color; };

  This is correct:

            
  
            struct  s_point
            {
              int   x;
              int   y;
              long  color;
            };
            
            

  
  
• Enumeration values SHOULD be capitalized or reasonably prefixed.

  Rationale: the use of common lowercase identifiers is discouraged because it clobbers the namespace.

• Enumeration values MUST appear on their own lines, properly aligned with the name of the enumeration.

  This is incorrect: enum e_boolean { true, false };

  This is correct:

            
  
            enum    e_boolean
            {
                    b_true,
                    b_false
            };
            
            

  
  

Declarations

• There MUST be only one declaration per line.
• Inner declarations (i.e. at the start of inner blocks) are RECOMMENDED when they can help improve compiler optimizations.
• Declaration blocks in functions SHOULD NOT contain extern declarations.
• Variables MAY be initialized at the point of declarations. However, for this purpose function and macro calls and composite expressions MUST NOT be used.

  The following is wrong: int foo = strlen("bar"); char c = (str++, *str);

  
  This is correct:

            
  
              unsigned int    *foo = &bar;
              unsigned int    baz = 1;
              static int      yay = -1;
            
            

  
  

  Hint: to detect uninitialized local variables, use the -O -Wuninitialized flags with GCC.