pointer of function in c

[abolfazlk873]

hi everybody
i am new in c programming, and i have a question about pointer of functions.
consider the code shown below:

uint8_t  [COLOR="#FF0000"]*[/COLOR]([COLOR="#0000FF"]*[/COLOR]GetConfigDescriptor)( uint8_t speed , uint16_t *length);

in the code there is two pointer for function in color of red and blue.
i know the task of the blue pointer but i don't know the task of red pointer.

what the task of red pointer?
i show the complete code below:

typedef struct _Device_cb
{
  uint8_t  (*Init)         (void *pdev , uint8_t cfgidx);
  uint8_t  (*DeInit)       (void *pdev , uint8_t cfgidx);
 /* Control Endpoints*/
  uint8_t  (*Setup)        (void *pdev , USB_SETUP_REQ  *req);  
  uint8_t  (*EP0_TxSent)   (void *pdev );    
  uint8_t  (*EP0_RxReady)  (void *pdev );  
  /* Class Specific Endpoints*/
  uint8_t  (*DataIn)       (void *pdev , uint8_t epnum);   
  uint8_t  (*DataOut)      (void *pdev , uint8_t epnum); 
  uint8_t  (*SOF)          (void *pdev); 
  uint8_t  (*IsoINIncomplete)  (void *pdev); 
  uint8_t  (*IsoOUTIncomplete)  (void *pdev);   

  uint8_t  [COLOR="#FF0000"]*[/COLOR]([COLOR="#0000FF"]*[/COLOR]GetConfigDescriptor)( uint8_t speed , uint16_t *length); 
#ifdef USB_OTG_HS_CORE 
  uint8_t  [COLOR="#FF0000"]*[/COLOR]([COLOR="#0000FF"]*[/COLOR]GetOtherConfigDescriptor)( uint8_t speed , uint16_t *length);   
#endif

#ifdef USB_SUPPORT_USER_STRING_DESC 
  uint8_t  [COLOR="#FF0000"]*[/COLOR]([COLOR="#0000FF"]*[/COLOR]GetUsrStrDescriptor)( uint8_t speed ,uint8_t index,  uint16_t *length);   
#endif  
  
} USBD_Class_cb_TypeDef;

 

[raja_rajan]

the called function is returning char * or uint8_t * or

the function is returning pointer of uint8_t.

 

[abolfazlk873]

ok, but in C programming when i decided to define pointer to the function like below:

int cmp(const char *, const char*));

pointer to this function is like below:

#include "string.h"
.
.
.
.
.
int ([COLOR="#0000FF"]*[/COLOR]p)(const char *, const char*);
p=strcmp;

but in this code there is no red pointer and the code is work well.
I want to know task of red pointer specified in the previous post.

 

[raja_rajan]

Hi,
Because it is not returning pointer. it is returning an integer.

int cmp(const char *, const char*));

int (*p)(const char *, const char*);
p=cmp; // it replace as int (cmp)(const char *, const char*);=int cmp (const char *, const char*);


if the function is returning pointer

then

int *cmp(const char *, const char*));

int *(*p)(const char *, const char*);