Archived

This topic is now archived and is closed to further replies.

Return local array from a function safely

This topic is 4944 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

Hi I am trying to return a local array from a function like this: char *getPathname() { char path[32]; // here I will store path "c:\file.txt" into path[] return path; } void main() { char *new_path = getPathname(); } but I am getting warnings that it is not safe to return a local address. Obviously becuase it will be destroyed when it is out of scope of the function. Fine. But what can I do in this case. I have to have same structure of char path[32]; just traditional array. I dont want any vectors etc.. I just need to know how to return safely this array so I can store the result in main() in another array. I dont care is if pass by copy or ref. its used once in the program and I am concerned with safety not speed. Can you please help? I guess I have somwhere my syntax wrong. I though the function prototype should be : char [] getPathname() rather than: char * getPathname but it didnt work at all. thanks [edited by - papa on May 30, 2004 5:27:33 AM]

Share this post


Link to post
Share on other sites
You should allocate the array dynamically (char *path = new char [32]), but then you''ll have to destroy it later somewhere in your main function. But I think, that strings are really nicer and there''s no reason not to use them.

Oxyd

- Unreadable code is code written on a piece of paper, but not the one, in which the programmer is using a space in the place you don''t.
- Real programmers aren''t afraid of goto

Share this post


Link to post
Share on other sites
Two options:

1) Return a newed array, but you have to remember to delete it in the calling-function.

2) Pass an array as a parameter, and fill the array in the local-funcion. Return whatever you like, or void.

--
You''re Welcome,
Rick Wong
- Google | Google for GameDev.net | GameDev.net''s DirectX FAQ. (not as cool as the Graphics and Theory FAQ)

Share this post


Link to post
Share on other sites
I want to add to PipoDeClown #2 option:

Pass both the (already allocated array) to the function, as well as an max size value.

eg:


int getPathname(char* buffer, int size){
// here you can store whatever you want in the array, as long as it fits in. (check with the size)


// as a return value you can (optionally) return the actual number of bytes you've copied to buffer

}

// you would use the funtion something like this

// allocate 32 byte array

char new_path[32];

// pass it to the function as well as the max size

getPathname(new_path, 32);

// use you new_path here





edit: typo


[edited by - Direct4D on May 30, 2004 1:31:12 PM]

Share this post


Link to post
Share on other sites