Problem with strtok and malloc

[full prism]

I do get the correct value with getNToken(), but when I try to free the memory it hangs.

char* getNToken(const char* str, const char* delim, const int pos)
{
    char* tmp = malloc(strlen(str)+1);
    strcpy(tmp,str);
    int pos_actual = 0;

    tmp = strtok(tmp,delim);
    while(pos_actual < pos)
    {
        tmp = strtok(NULL,delim);
        pos_actual++;
    }

    return tmp;
}

int main()
{
    char* d = getNToken("aaa,bbb,ccc",",",1);
    printf("%s\n",d);
    free(d);
    return 0;
}

[brittle trellis]

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[halcyon hatch]

you need to give the pointer you got from malloc to free

i.e. it has to point to the start of the memory block

the tmp pointer you return will point to the middle of the memory block

[full prism]

so, doing free(d-(strlen(d)+1)) would be correct?

[halcyon hatch]

i would just return two pointers. one to the start of the memory block (so you can free it) and one to the token

for example you could add another parameter char **tofree which you set to the start of the memory block.

char *tmp = malloc(...);
*tofree = tmp;

// later in the main function
char *tofree;
char *d = getNToken(..., &tofree);
// the rest
free(tofree);

[full prism]

thx!

!solved

[brittle trellis]

Thank you and let us know if you have any more questions!

[SOLVED] Problem with strtok and malloc

[brittle trellis]

Problem with strtok and malloc