From af5b509c7533bdc86cef923d53fd5e2daf692036 Mon Sep 17 00:00:00 2001 From: Paul Sokolovsky Date: Sat, 20 Oct 2018 12:36:48 +0300 Subject: [PATCH] examples/unix/ffi_example: Clean up and update the ffi example. 1. Use uctypes.bytearray_at(). Implementation of the "ffi" module predates that of "uctypes", so initially some convenience functions to access memory were added to ffi. Later, they landed in uctypes (which follows CPython's ctype module). So, replace undocumented experimental functions from ffi to documented ones from uctypes. 2. Use more suitable type codes for arguments (e.g. "P" (const void*) instead of "p" (void*). 3. Some better var naming. 4. Clarify some messages printed by the example. --- examples/unix/ffi_example.py | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) diff --git a/examples/unix/ffi_example.py b/examples/unix/ffi_example.py index f650e3370..3c3c3d239 100644 --- a/examples/unix/ffi_example.py +++ b/examples/unix/ffi_example.py @@ -1,4 +1,5 @@ import ffi +import uctypes libc = ffi.open("libc.so.6") print("libc:", libc) @@ -8,7 +9,7 @@ print() perror = libc.func("v", "perror", "s") time = libc.func("i", "time", "p") open = libc.func("i", "open", "si") -qsort = libc.func("v", "qsort", "piip") +qsort = libc.func("v", "qsort", "piiC") # And one variable errno = libc.var("i", "errno") @@ -16,23 +17,23 @@ print("time:", time) print("UNIX time is:", time(None)) print() -perror("ffi before error") +perror("perror before error") open("somethingnonexistent__", 0) print("errno object:", errno) print("errno value:", errno.get()) -perror("ffi after error") +perror("perror after error") print() def cmp(pa, pb): - a = ffi.as_bytearray(pa, 1) - b = ffi.as_bytearray(pb, 1) + a = uctypes.bytearray_at(pa, 1) + b = uctypes.bytearray_at(pb, 1) print("cmp:", a, b) return a[0] - b[0] -cmp_c = ffi.callback("i", cmp, "pp") -print("callback:", cmp_c) +cmp_cb = ffi.callback("i", cmp, "PP") +print("callback:", cmp_cb) s = bytearray(b"foobar") print("org string:", s) -qsort(s, len(s), 1, cmp_c) +qsort(s, len(s), 1, cmp_cb) print("qsort'ed string:", s)