standard io library: fopen
change source file mode 755
standard io library: fread()
standard io library: fwrite()
standard io library: fclose()
standard io library: fflush()
standard io library: fseek()
standard io library: fgetc(), getc(), getchar()
standard io library: fputc(), putc(), putchar()
standard io library: fgets(), gets()
Merge branch 'develop'