MISRA.TOKEN.CPCOM.MULTILINE.2012

Line-splicing used in a // comment

MISRA 2012 C Rule 3.2: Line-splicing shall not be used in // comments

Category: Required

Analysis: Decidable, Single Translation Unit

Applies to: C99

Amplification

Line-splicing occurs when the \ character is immediately followed by a new-line character. If the source file contains multibyte characters, they are converted to the source character set before any splicing occurs.

Rationale

If the source line containing a // comment ends with a \ character in the source character set, the next line becomes part of the comment. This may result in unintentional removal of code.

Note: line-splicing is described in Section 5.1.1.2(2) of both C90 and C99.

Example

In the following non-compliant example, the physical line containing the if keyword is logically part of the previous line and is therefore a comment.

extern bool_t b;

void f ( void ) 
{
  uint16_t x = 0; // comment \ 
  if ( b ) 
  {
    ++x;          /* This is always executed */ 
  } 
}

See also

Dir 4.4