Locates the first occurrence of the specified byte within the
    initial size bytes of a given object.

    Format

      #include  <string.h>

      void *memchr  (const void *s1, int c, size_t size);

1 - Function Variants

    The memchr function has variants named _memchr32 and _memchr64
    for use with 32-bit and 64-bit pointer sizes, respectively.

2 - Arguments

 s1

    A pointer to the object to be searched.

 c

    The byte value to be located.

 size

    The length of the object to be searched.

    If size is zero, memchr returns NULL.

3 - Description

    Unlike strchr, the memchr function does not stop when it
    encounters a null character.

4 - Return Values

    pointer            A pointer to the first occurrence of the byte.
    NULL               Indicates that the specified byte does not
                       occur in the object.