The Ten Commandments for C Programmers

Henry Spencer

  1. Thou shalt run Lint frequently and study its pronounce-
    ments with care, for verily its perception and judge-
    ment oft exceed thine.
  2. Thou shalt not follow the NULL pointer, for chaos and
    madness await thee at its end.
  3. Thou shalt cast all function arguments to the expected
    type if they are not of that type already, even when
    thou art convinced that this is unnecessary, lest they
    take cruel vengeance upon thee when thou least expect
  4. If thy header files fail to declare the return types of
    thy library functions, thou shalt declare them thyself
    with the most meticulous care, lest grievous harm
    befall thy program.
  5. Thou shalt check the array bounds of all strings
    (indeed, all arrays), for surely where thou typest
    ``foo'' someone someday shall type ``supercalifragilis-
  6. If a function be advertised to return an error code in
    the event of difficulties, thou shalt check for that
    code, yea, even though the checks triple the size of
    thy code and produce aches in thy typing fingers, for
    if thou thinkest ``it cannot happen to me'', the gods
    shall surely punish thee for thy arrogance.
  7. Thou shalt study thy libraries and strive not to re-
    invent them without cause, that thy code may be short
    and readable and thy days pleasant and productive.
  8. Thou shalt make thy program's purpose and structure
    clear to thy fellow man by using the One True Brace
    Style, even if thou likest it not, for thy creativity
    is better used in solving problems than in creating
    beautiful new impediments to understanding.
  9. Thy external identifiers shall be unique in the first
    six characters, though this harsh discipline be irksome
    and the years of its necessity stretch before thee
    seemingly without end, lest thou tear thy hair out and
    go mad on that fateful day when thou desirest to make
    thy program run on an old system.
  10. Thou shalt foreswear, renounce, and abjure the vile
    heresy which claimeth that ``All the world's a VAX'',
    and have no commerce with the benighted heathens who
    cling to this barbarous belief, that the days of thy
    program may be long even though the days of thy current
    machine be short.