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

I am not clear. Do you want:

• to concatenate every one of the 10 character buffers you receive into one array, pointed at by one real[0].buffer, or
• do you want each 10 character buffer to be pointed at by a different real[i].buffer, or
• something else?

You will need to allocate enough space for the copy of the buffer:

#include 
//...
int size = 10+1; // need to allocate enough space for a terminating '\0'
char* buff = (char *)malloc(size);   
if (buff == NULL) {
    fprintf(stderr, "Error: Failed to allocate %d bytes in file: %s, line %d\n,
                     size, __FILE__, __LINE__ );
    exit(1);
}
buff[0] = '\0';    // terminate the string so that strcat can work, if needed
//...
real[i].buffer = buff;  // now buffer points at some space
//...
strncpy(real[i].buffer, buffer, size-1);