运行时出错。 类型冲突和先前的声明

Question

I found an implementation of AES for a project I'm doing.

However when i integrate it I'm getting the following errors during the build.

In file included from ff.h:26:0,
             from disp.h:4,
             from main.c:14:
aes.h:14:3: error: conflicting types for 'AesCtx'
aes.h:14:3: note: previous declaration of 'AesCtx' was here
aes.h:28:5: error: conflicting types for 'AesCtxIni'
aes.h:28:5: note: previous declaration of 'AesCtxIni' was here
aes.h:29:5: error: conflicting types for 'AesEncrypt'
aes.h:29:5: note: previous declaration of 'AesEncrypt' was here
aes.h:30:5: error: conflicting types for 'AesDecrypt'
aes.h:30:5: note: previous declaration of 'AesDecrypt' was here

The header file itself is:

// AES context structure
typedef struct {
 unsigned int Ek[60];
 unsigned int Dk[60];
 unsigned int Iv[4];
 unsigned char Nr;
 unsigned char Mode;
} AesCtx;

// key length in bytes
#define KEY128 16
#define KEY192 24
#define KEY256 32
// block size in bytes
#define BLOCKSZ 16
// mode
#define EBC 0
#define CBC 1

// AES API function prototype

int AesCtxIni(AesCtx *pCtx, unsigned char *pIV, unsigned char *pKey, unsigned int KeyLen, unsigned char Mode);
int AesEncrypt(AesCtx *pCtx, unsigned char *pData, unsigned char *pCipher, unsigned int DataLen);
int AesDecrypt(AesCtx *pCtx, unsigned char *pCipher, unsigned char *pData, unsigned int CipherLen);

and then the respective C file uses.

int AesCtxIni(AesCtx *pCtx, unsigned char *pIV, unsigned char *pKey, unsigned int KeyLen, unsigned char Mode)
{
    // Cut out code for brevity
}

int AesEncrypt(AesCtx *pCtx, unsigned char *pData, unsigned char *pCipher, unsigned int DataLen)
{
    // Cut out code for brevity
}

int AesDecrypt(AesCtx *pCtx, unsigned char *pCipher, unsigned char *pData, unsigned int CipherLen)
{
    // Cut out code for brevity
}

I know these errors usually occur because either the function hasn't been pre-declared or because it's slightly different to it's declaration, but I can't see a difference.

Any ideas?

Answer 1

What compiler are you using? My best guess that it's trying to say aes.h is being #include d twice. Try adding header guards at the beginning and end of the aes.h :

#ifndef AES_H_
#define AES_H_

typedef struct {
...
int AesDecrypt(AesCtx *pCtx, unsigned char *pCipher, unsigned char *pData, unsigned int CipherLen);

#endif /* !AES_H_ */