test_verify.py 文件源码

def test_FILE_stored_explicitly():
    ffi = FFI()
    ffi.cdef("int myprintf11(const char *, int); FILE *myfile;")
    lib = ffi.verify("""
        #include <stdio.h>
        FILE *myfile;
        int myprintf11(const char *out, int value) {
            return fprintf(myfile, out, value);
        }
    """)
    import os
    fdr, fdw = os.pipe()
    fw1 = os.fdopen(fdw, 'wb', 256)
    lib.myfile = ffi.cast("FILE *", fw1)
    #
    fw1.write(b"X")
    r = lib.myprintf11(b"hello, %d!\n", ffi.cast("int", 42))
    fw1.close()
    assert r == len("hello, 42!\n")
    #
    result = os.read(fdr, 256)
    os.close(fdr)
    # the 'X' might remain in the user-level buffer of 'fw1' and
    # end up showing up after the 'hello, 42!\n'
    assert result == b"Xhello, 42!\n" or result == b"hello, 42!\nX"