When assigning pointer to pointer I get warning: assignment makes integer from pointer

Question

I hate posting this because there are so many of these, but none of them seem to address what I am seeing. The normal issues (undeclared functions, unintentional casts, misunderstanding of basic pointers) don't seem apply here. This is the stripped down version of my code:

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>

extern void* malloc ( size_t size );

typedef struct {
    size_t      size;
    uint8_t*    buffer, curr, next;
} buffer_t;

void init( buffer_t* b, int size ) {
    b->size   = (size_t) size;
    b->buffer = (uint8_t*) malloc( sizeof(uint8_t) * b->size + 1 );
    b->curr   = (uint8_t*) b->buffer; // warning: assignment makes integer from pointer without a cast [enabled by default]
    b->next   = (uint8_t*) b->buffer; // warning: assignment makes integer from pointer without a cast [enabled by default]
}

int main ( int argc, char* argv[] ) {
    buffer_t buf;

    init( &buf, 16 );

    return 0;
}

This fails without the casts, but putting them in makes it even more obvious.

I'm compiling on WinXP (yeah, yeah, yeah) under MinGW/MSYS with gcc 4.7.2. using the following command:

gcc -std=c99 -Wall -o testing test.c

Any help?

Answer 1

uint8_t*    buffer, curr, next;

The way you wrote it, buffer is a pointer and curr and next are mere uint8_ts. You probably meant:

uint8_t    *buffer, *curr, *next;

Even better (less prone to errors) would be to have each field on its own line.