C int to char array on Mac OS X

Question

I'm trying to convert an int to a char*. I'm on a Mac OS X so I can't use itoa, since it's non-standard, I'm trying to use sprintf or snprintf but I keep on getting segmentation fault: 11. Here's what I've got:

snprintf(msg, sizeof(char *), "%d", 1);

So I'm hoping for a suggestion, what can I do?

I'm guessing that `msg` is a `char *` that hasn't had any memory allocated to it, yes? — AntonH, Jul 05 '14 at 03:44
Then I'm guessing that you haven't allocated any memory to it. Lemme write an answer out. — AntonH, Jul 05 '14 at 03:49
yeah, that was it, sorry for such a simple mistake... I didn't thought that it had to be allocated first. — C. Porto, Jul 05 '14 at 03:52

AntonH · Accepted Answer · 2014-07-05T22:34:44.557

It's likely that msg, which is a char *, doesn't point to memory that it can use. So you first have to dynamically allocate memory that will be used to store the string.

msg = malloc(12); // 12 is an arbitrary value
snprintf(msg, 12, "%d", 1); // second parametre is max size of string made by function

Alternatively, you can instead declare a static buffer. That way, you won't have to free any memory.

char msg[12]; // again, 12 is an arbitrary value
snprintf(msg, sizeof(msg), "%d", 1);

score 0 · Answer 2 · answered Jul 05 '14 at 03:46

0

How do you declare msg?

Something like this should work:

char msg[15];
snprintf(msg, sizeof(msg), "%d", 1);

Note that the second argument to snprintf is the length of the string, not the size of a character.

answered Jul 05 '14 at 03:46

user3553031

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C int to char array on Mac OS X

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