c - Segmentation fault using strcat

Question

Here is my code :

char *name, name_log="log-";

------getting 'name' from user-----

strcat(name_log, name);
char ext[] = ".log";
strcat(name_log, ext);

What i need to end up with is name_log = "log-'name'.log" but Im getting a segmentation fault error :((. What am I doing wrong and how can I fix it ? Thx

Answer 1

string literals get allocated a fixed amount of memory, generally in a read only section, you instead need to use a buffer.

char buffer[64] = "log-";
strncat(buffer,".log",32);

On a side note, strcat is generally unsafe, you need to use something that that checks the size of the buffer it uses or with limits on what it can concatenate, like strncat.