A question about function returning pointers to ram

[future]

Hi,

How to have functions returning pointers to ram strings without global arrays?

I mean, a function prototyped as char *myfunction( char value ); returning the ascii representation of the value for the printf( "%s", myfunction(10) );.
myfunction would have to do its work with a global array.

So I declare it, but a long printf( "%s %s %s", , myfunction(10), myfunction(20), myfunction(30) ); would need 3 global arrays.

How about other solutions?

Thank you.

[Neutone]

What you ask to do with function pointers can not be done on a PIC in an efficient manner.

What information is it that you wish to display? What format do you wish to display it in?

[future56]

It´s not function pointers, but functions returning pointers to ram.

I want to convert many variables to a readable format and display them. So if I need to show 100 counts of 5ms, I´d call the convert function passing 100 to it and it returns a pointer to a string containing "500mS".

I can have a function for each kind of variable and just call them using printf when I need.

One solution is allocating many global arrays and pass the variable and array address to the function and it returns the same array address, but I have to take care of array usage myself when many conversions are needed in the same printf (need 8 at some places).

printf( "%s %s %s %s", myfunction( 100, array1), myfunction( 10, array2), myfunction( 200, array3), myfunction( 300, array4) )

There is another problem with printf not liking more than 3 strings, but this will be addressed later.

Maybe there is a clever way to do this.

Thank you.

[Ttelmah]

This is what the memory handling functions, in memmgmt.c, are designed to handle. When the functon is first called, have it generate a node, using a static variable to store the 'node_t' variable. Then on future calls, work out how long the string needs to be, and use the 'update_node' function, to change the size.
Then when you have finished with the memory, use 'remove_node' to free the space.
Unfortunately, the space has to be pre-allocated, so unless you have other code that also uses the same memory handling ability, you will not save anything. Also, the calls can beccome rather unreliable...
Personally, I'd probably just allocate a static area to hold the returns, or have the calling program, give the function the location it wants the result to be put into.

Best Wishes

[future]

Ok, I'll have static arrays declared inside each function and see how it goes.

Thank you.

[libor]

[future]