Read file contents with unknown size

Question

I want to process the contents of a config file. The config file could be any size. I am getting a Bus Error, after the program hangs, when I run the following code:

Answer 1

In C99, and assuming your config file should not be in the MiB or larger range, you could use a VLA:

FILE *fp = fopen(CONFIG_FILE, "r");
if (fp == NULL) {
    // error handling and cleanup omitted for brevity
}

struct stat st;
fstat(fileno(fp), &st);  // Error check omitted
char buffer[st.st_size+1];
fread(buffer, sizeof(char), st.st_size, fp);
buffer[st.st_size] = '\0';
fprintf(stderr, "%s\n", *buffer);
fclose(fp);