C array of array of strings

Question

In C, I need to statically pre-allocate an array of numbers, each associated with a different array of strings. Will a code like the following do the trick:

struct number_and_strings {
  int  nnn;
  char **sss;
}

static struct number_and_strings my_list[] = {
  {12, {"apple","banana","peach","apricot","orange",NULL}},
  {34, {"tomato","cucumber",NULL}},
  {5,  {"bread","butter","cheese",NULL}},
  {79, {"water",NULL}}
}

What I fear is that it will seem to work, but due to some misunderstanding of pointers I will end up gulping or leaking memory. — Free Bud
– Free Bud, Commented Apr 13, 2013 at 16:13
The pointers will point at memory locations in the data segment. No leaking there. — Bart Friederichs
– Bart Friederichs, Commented Apr 13, 2013 at 16:15
No, it will not work. An array is not a pointer, so you can't initialize a pointer to pointer with an initializer for array of string. — Jens Gustedt
– Jens Gustedt, Commented Apr 13, 2013 at 16:15

P.P · Accepted Answer · 2013-04-13 16:19:40Z

5

sss is a pointer to pointer. So an array of pointers can't be directly assigned to it. You can assign as follows using compound literals (which is a C99 feature):

static struct number_and_strings my_list[] = {
      {12, (char*[]){"apple","banana","peach","apricot","orange",NULL}},
      {34, (char*[]){"tomato","cucumber",NULL}},
      {5,  (char*[]){"bread","butter","cheese",NULL}},
      {79, (char*[]){"water",NULL}}
    };

answered Apr 13, 2013 at 16:19

P.P

122k20 gold badges193 silver badges251 bronze badges

Sign up to request clarification or add additional context in comments.

6 Comments

Jens Gustedt Over a year ago

This is not a cast, but something quite different, namely a compound literal. (C jargon and syntax for an unnamed object)

P.P Over a year ago

@FreeBud No, AFAIK C89/90 doesn't support it (but gcc supports it as an extension). If you compile in C99 mode, it should be fine. For example, if you are using gcc, then: gcc -std=c99 file.c.

Free Bud Over a year ago

Let me ask that differently: What changes can I put in the struct definition (or other changes), in order for the static array to be declared this way (or similarly), using ANSI C?

P.P Over a year ago

@FreeBud What is the compiler that you are you using? First directly copy the struct declaration in my answer and try.

Free Bud Over a year ago

>> What is the compiler that you are you using -- it's tricky. I'm using Digital Mars C on my Windows PC, but the ultimate destination is to be included as part of an Objective C code on an Apple.

|

Collectives™ on Stack Overflow

C array of array of strings

1 Answer 1

6 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

6 Comments

Your Answer

Sign up or log in

Post as a guest

Related