Passing array string into function pointer?

Question

I guess something is fundamentally wrong, I would like to send this global :

static char content[MAX_NUM_WORDS][MAX_WORD_LEN];

as an argument to a function pointer , where the function pointer def :

void(*flashReadDelegate)(char*[])=0;

and calling it with :

//save some data in (which prints ok)
strcpy(content[record_desc.record_id],toSave);

// ***Send the delegate out
(*flashReadDelegate)(content);  // ** here there is a compiler warnning about the argument

So how should the pointer argument look like if I want to send content ?

haccks · Accepted Answer · 2017-05-30 20:25:25Z

5

void(*flashReadDelegate)(char*[])=0; is wrong. Your function pointer should be like this

void (*flashReadDelegate)(char (*)[MAX_WORD_LEN]);

You have not mentioned the prototype of the function to which flashReadDelegate is pointing. I am assuming that it's prototype would be

void func(char (*)[MAX_WORD_LEN]);

Now, in the function call (*flashReadDelegate)(content);, the argument array content will be converted to a pointer to an array of MAX_WORD_LEN chars ((*)[MAX_WORD_LEN]).

edited May 30, 2017 at 20:25

answered May 30, 2017 at 20:21

haccks

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3 Comments

Curnelious Over a year ago

Thanks a lot! So why is my arg wrong? Isn't it a pointer to strings?

haccks Over a year ago

@Curnelious; As a function parameter char*[] is equivalent to char**.

Zakir Over a year ago

Well char*[] reduces to pointer to the 1st element of an array of characters where as char (*)[MAX_WORD_LEN] reduces to a pointer to an array of characters with each array element being MAX_WORD_LEN characters wide

OlivierM · Accepted Answer · 2017-05-30 20:37:04Z

1

Your declaration of content is not a pointer to strings. It is an array of MAX_NUM_WORDS strings of MAX_WORD_LEN characters.

If you want an array of strings you would need to declare content as: static char* content[MAX_NUM_WORDS];`

answered May 30, 2017 at 20:37

OlivierM

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