cat.c

#include <stdlib.h>
#include <stdio.h>
#include <errno.h>

enum { buf_max = 32, };

int main(int argc, char* argv[argc+1]) {
  int ret = EXIT_FAILURE;
  char buffer[buf_max] = { 0 };
  for (int i = 1; i < argc; ++i) {        // Processes args
    FILE* instream = fopen(argv[i], "r"); // as filenames
    if (instream) {
      while (fgets(buffer, buf_max, instream)) {
        fputs(buffer, stdout);
      }
      fclose(instream);
      ret = EXIT_SUCCESS;
    } else {
      /* Provides some error diagnostic. */
      fprintf(stderr, "Could not open %s: ", argv[i]);
      perror(0);
      errno = 0;                       // Resets the error code
    }
  }
  return ret;
}