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"assignment discards 'const' qualifier" error on non-const pointer

In the following function:

char *mystrtok(const char *input, const char *delim,char *rest) {
    int i;
    for (i = 0; input[i] != *delim && input[i] != '\0'; ++i) {
        continue;
    }
    char *result = malloc(sizeof(char) * (i + 2));
    memcpy(result, input, i + 1);
    result[i + 1] = '\0';
    if (input[i + 1] != '\0') 
        rest = input + i + 2;
    else
        rest = NULL;
    return result;
}

I am getting assignment discards 'const' qualifier from pointer target type for the line rest = input + i + 2, however, as you can see, rest is not a constant pointer. What am I doing wrong here?

like image 249
yasar Avatar asked Apr 11 '12 20:04

yasar


2 Answers

input is a pointer to a constant char, and you're assigning it to a pointer to a non-constant char. This here might be an interesting reading for you.

like image 50
littleadv Avatar answered Oct 15 '22 05:10

littleadv


you could also cast your 'input' variable with a (char*) type which would resolve the warning. just be careful using explicit casts like this so as not to modify constants themselves.

rest = (char*)input + i + 2;
like image 21
midnightCoder Avatar answered Oct 15 '22 06:10

midnightCoder