how will i pass the path of a file name to void *buffer using c language?

Question

implementing ProcessRequest and wants to copy data into buffer to return to the caller

The function signature is he following :
int ProcessRequest(HCST hCST, void *buffer, short tag, short status)

path name of the file is stored in char src [40] ;

Answer 1

You need this :

int ProcessRequest(int hCST, void *buffer, short tag, short status)
{
  // stub function 
  static char test[] = "Test";
  strcpy(buffer, test);
  return 0;
}

...
char src [40];
...
ProcessRequest(myhCST, src, mytag, mystatus);
/* now src contains "Test" */

This code is very simple and unsafe because ProcessRequest doesn't know the size of buffer and hence may potentially overwrite past the end of buffer .