from c_import import loader
import ctypes

libc = loader.load("libc.so.6", ["stdio.h", "stdint.h", "math.h", "stdlib.h", "string.h", "time.h"])

# Work with file streams
filestream = libc.fopen(b"/tmp/x", b"rw+")
text = ctypes.create_string_buffer(b"Hello world")
libc.fwrite(text, len(text), 1, fstream)
libc.fflush(fstream)
libc.fclose(fstream)

libc.fileno(libc.stdin)
# 1

libc.fputc(ord('A'), libc.stdout)
libc.fflush(libc.stdout)
# A
libc.fprintf(libc.stderr, b"%d\n", 100) # 100

# Use math functions
libc.abs(-1)
# 1

# Create instances of structs
cal_date = libc.tm()
dir(cal_date)
# All fields are available
# [...,
#  'tm_gmtoff',
#  'tm_hour',
#  'tm_isdst',
#  'tm_mday',
#  'tm_min',
#  'tm_mon',
#  'tm_sec',
#  'tm_wday',
#  'tm_yday',
#  'tm_year',
#  'tm_zone']
cal_date.tm_sec = 1
cal_date.tm_year = 1999

# View the fields of "private" structs
# Great when experimenting inside an interactive shell.
dir(libc.stdout.contents)
# (Fields differ between libc implementations)
# [...,
#  '_IO_backup_base',
#  '_IO_buf_base',
#  '_IO_buf_end',
#  '_IO_read_base',
#  '_IO_read_end',
#  '_IO_read_ptr',
#  '_IO_save_base',
#  '_IO_save_end',
#  '_IO_write_base',
#  '_IO_write_end',
#  '_IO_write_ptr',
#  '__pad5',
#  '_chain',
#  '_codecvt',
#  '_cur_column',
#  '_fields_',
#  '_fileno',
#  '_flags',
#  '_flags2',
#  '_freeres_buf',
#  '_freeres_list',
#  '_lock',
#  '_markers',
#  '_mode',
#  '_objects',
#  '_offset',
#  '_old_offset',
#  '_shortbuf',
#  '_unused2',
#  '_vtable_offset',
#  '_wide_data']
libc.stdout.contents._fileno # 1

# Functions that return a struct work too
x = libc.div(49, 8)
x.quot # 6
x.rem  # 1
x.__class__.__name__ # 'div_t'

# Abort the process
libc.abort()