Re: A question regarding C string functions

On 2025-04-02, Lew Pitcher <lew.pitcher@digitalfreehold.ca> wrote:

I cannot find any definitive statement in my copies of the various
C language standards that addresses the behaviour of the C string
functions when given a NULL pointer.

Let us start with ISO C 90.

  7.1.7 Use of library functions
 
  Each of the following statements applies unless explicitly stated
  otherwise in the detailed descriptions that follow. If an argument to
  a function has an invalid value (such as a value outside the domain of
  the function. or a pointer outside the address space of the program.
  or a null pointer), the behavior is undefined.
  ^^^^^^^^^^^^^^^^^

C99 draft. (Have the real thing, not currently on me):

  7.1.4 Use of library functions

  1 Each of the following statements applies unless explicitly stated
    otherwise in the detailed descriptions that follow: If an argument
    to a function has an invalid value (such as a value outside the
    domain of the function, or a pointer outside the address space of
    the program, or a null pointer, or a pointer to non-modifiable
    storage when the corresponding parameter is not const-qualified) or
    a type (after promotion) not expected by a function with variable
    number of arguments, the behavior is undefined.

n3301 draft:

  7.1.4 Use of library functions

  1 Each of the following statements applies unless explicitly stated
    otherwise in the detailed descriptions that follow:

    -- If an argument to a function has an invalid value (such as a
       value outside the domain of the function, or a pointer outside
       the address space of the program, or a null pointer, or a pointer
       to non-modifiable storage when the corresponding parameter is not
       const-qualified) or a type (after default argument promotion) not
       expected by a function with a variable number of arguments, the
       behavior is undefined.

It gets more verbose and indented, but the null treatment is
consistently there.

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