Thread: Why does this malloc give me a segmentation fault?

Code:

    f = fopen("test1.txt", "r");
    if (f == NULL) {
        printf("Could not open file.\n");
        exit(1);
    }
    //Memory allocation for output file name
    output_titles = (char*)malloc(sizeof(char*)*(strlen(strcat("test1.txt", ".titles"))+1));

    //Creation of output file name
    strcpy(output_titles, strcat("test1.txt", ".titles"));

I'm getting a segmentation fault, and it seems to be happening because of wrong use of malloc. But why is this wrong?