The system_fopenRO function opens the file identified by path in read-only mode and returns a valid file descriptor. Use this function to open files that will not be modified by your program. In addition, you can use system_fopenRO to open a new file buffer structure using filebuf_open.
SYS_FILE system_fopenRO(char *path);
The system-independent file descriptor (SYS_FILE) if the open succeeded, or 0 if the open failed.
char *path is the file name.