CODEWITHSUNDEEP
cmalloc
kinezana
kinezana

Reputation: 83

proper malloc bug fixing

I had this line of code : 

conf->table = malloc(sizeof(struct Categorie)*(csv_nbLines(filename)));

that led to a bug when calling free() on conf because struct Categorie include a string (array of chars).

I fixed the bug by replacing the sizeof(struct Categorie) with 30 because I know the said string will not go over 30 bytes.

Is this acceptable ? If not what would be a better way to malloc the exact amount of memory needed ?

EDIT :

struct Categorie {
    char *name;
    char c;
};

EDIT2 :

I end up with this and it works perfectly (the names speaks for themselves).

in conf_init()

conf->table = malloc(sizeof(struct Categorie))

in conf_load() where pch is a string returned by strtok()

conf->table[i].name = malloc(sizeof(char)*strlen(pch));
conf->table[i].name = pch;

I hope this is enough explanation for the next one :)

Upvotes: 1

Views: 235

Answers (2)

Persixty
Persixty

Reputation: 8589

Answer: No. That is not acceptable.

You need to provide more code to understand what is going on, but assuming conf->table is struct Categorie * then there's something pretty rotten.

If that isn't the type then it's not clear why you ever thought sizeof(struct Categorie) might be the answer.

Upvotes: 1

Sourav Ghosh
Sourav Ghosh

Reputation: 134336

I'm afraid, NO.

Assuming the string you mentioned is in form of

struct Categorie
{

.
.
char * str;
}

You're supposed to first malloc() the memory for conf->table with sizeof(struct Categorie), and then, malloc() for conf->table->str.

Not to mention, free()ing also required, in the exact opposite oreder of allocation, i.e, first you need to free conf->table->str and then conf->table.

Upvotes: 4

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