• State Not Answered
  • Locked Locked
  • Replies 4 replies
  • Subscribers 21 subscribers
  • Views 683 views
  • Users 0 members are here
2025 survey

We are running a survey to help us improve the experience for all of our members. If you see the survey appear, please take the time to tell us about your experience if you can.

Options
Related
How was your experience today?
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

pointer to code memory

ganesh mutha

hello every one

i am trying to create a pointer to two dimensional character array located in code space of 8051

i am getting a warning of c182:pointer to different objects

my code is like this

unsigned char code table[120][5]={some values}//array daclaration

unsigned char code **ptr;//pointer to code memory

ptr = table;//trying to access this way

can any one tell what is the mistake in it

thanks®ards
ganesh

Parents
  • 0

    You've fallen prey to the common misconception that pointers and arrays are fully interchangeable in C. They're not.

    In particular, a pointer to an array of a multi-dimensional array is not constructed as a pointer-to-pointer-...to-element.

    Correct code (setting aside the additional complication of the "code" keyword) would be any of

    unsigned char (*ptr_to_whole_array)[120][5] = &table;
unsignec char (*ptr_to_first_row)[5] = table;
unsigned char *ptr_to_element = table[0];

Reply
  • 0

    You've fallen prey to the common misconception that pointers and arrays are fully interchangeable in C. They're not.

    In particular, a pointer to an array of a multi-dimensional array is not constructed as a pointer-to-pointer-...to-element.

    Correct code (setting aside the additional complication of the "code" keyword) would be any of

    unsigned char (*ptr_to_whole_array)[120][5] = &table;
unsignec char (*ptr_to_first_row)[5] = table;
unsigned char *ptr_to_element = table[0];

Children