How to concat two char * in C?

Question

I receive a char * buffer which have the lenght of 10. But I want to concat the whole content in my struct which have an variable char *.

typedef struct{
            


        

Answer 1

In general, do the following (adjust and add error checking as you see fit)

// real[i].buffer += buffer; 

   // Determine new size
   int newSize = strlen(real[i].buffer)  + strlen(buffer) + 1; 

   // Allocate new buffer
   char * newBuffer = (char *)malloc(newSize);

   // do the copy and concat
   strcpy(newBuffer,real[i].buffer);
   strcat(newBuffer,buffer); // or strncat

   // release old buffer
   free(real[i].buffer);

   // store new pointer
   real[i].buffer = newBuffer;