Thread: help needed with dereferencing pointer to incomplete type error

So heres my code:

Code:

char buf[256]; 
struct rtp_hdr_t *header = (struct rtp_hdr_t *) buf;

memset(buf,0,256); 
header->version = 2;
header->p = 0;
header->x = 0;
header->cc = 0;
header->m = 0;
header->pt = 0;
header->seq = htons(0);
header->ts = htons(0);

Im getting the error in all the assignment lines.

Heres rtp_hdr_t:

Code:

typedef struct {
#if RTP_BIG_ENDIAN
    unsigned int version:2;   /* protocol version */
    unsigned int p:1;         /* padding flag */
    unsigned int x:1;         /* header extension flag */
    unsigned int cc:4;        /* CSRC count */
    unsigned int m:1;         /* marker bit */
    unsigned int pt:7;        /* payload type */
#elif RTP_LITTLE_ENDIAN
    unsigned int cc:4;        /* CSRC count */
    unsigned int x:1;         /* header extension flag */
    unsigned int p:1;         /* padding flag */
    unsigned int version:2;   /* protocol version */
    unsigned int pt:7;        /* payload type */
    unsigned int m:1;         /* marker bit */
#else
#error Define one of RTP_LITTLE_ENDIAN or RTP_BIG_ENDIAN
#endif
    unsigned int seq:16;      /* sequence number */
    u_int32 ts;               /* timestamp */
    u_int32 ssrc;             /* synchronization source */
    u_int32 csrc[1];          /* optional CSRC list */
} rtp_hdr_t;

Im honestly not very good working with pointers and i cant see where the problem is here. Pls help... Thanks!

Your code defines nothing called "struct rtp_hdr_t". So you can't try to assign to such a thing, since it doesn't exist. (You do have such a thing as "rtp_hdr_t", though; maybe you could use that instead.)

i do define the struct rtp_hdr_t. Thats the second part.


Im not following what u mean....

The second part of your code defines nothing that is called "struct rtp_hdr_t". It does define a type called "rtp_hdr_t". Yes, there is a difference.

Edit: To be more precise, this is "struct rtp_hdr_t":

Code:

struct rtp_hdr_t {
    stuff;
};

This is "rtp_hdr_t":

Code:

typedef struct {
    stuff;
} rpt_hdr_t;

It worked like a charm! thanks!