warning: Incompatible integer to pointer conversion assigning to 'char *' to int

Hi all, when I use the function to concat the pointer, the warning message is come out (Incompatible integer to pointer conversion assigning to 'char *' to 'int'), how can I fix this, many thanks!!

Code:

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char* concat(char* left,char* right)
{
    char* all = malloc(strlen(left)+strlen(right)+1);
    strcpy(all, left);
    strcat(all, right);
    puts(all);
    free(all);
    return all;
}

//use the concat function like this:
char* all;
char* tmp="abc";
all = concat("06",tmp); //warning msg here "sc means concat"

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I notice that you are calling a mysterious function named sc, not your concat function.

Besides this, there is the issue that you called strcpy before initialising what all points to, i.e.,

Code:

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all[0] = '\0';

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should have come before the strcpy call. You should also check that malloc did not return a null pointer.

Then, it makes no sense to free(all) then return all; Perhaps you should free in the caller instead.

Oh, and since you are not modifying what left and right point to, you should declare them to be const char* instead.

> should have come before the strcpy call. You should also check that malloc did not return a null pointer.
strcpy does not depend on the initial contents of the destination (whereas strcat does).

Since you 'free' the memory inside the function don't expect the caller to have valid contents in the string.