From: Anthony Green <green@moxielogic.com>
To: ShaJunxing <shajunxing@163.com>
Cc: libffi-discuss <libffi-discuss@sourceware.org>
Subject: Re: How to call 'printf' using libffi?
Date: Thu, 18 Mar 2021 11:25:01 -0400 [thread overview]
Message-ID: <CACxje5-Us3WkCtDZwOzWik7PL_YK0LU7tf6_X+tW5R5mQiPK1A@mail.gmail.com> (raw)
In-Reply-To: <00aed94e-6f76-f6d7-9878-a3eb50dce543@163.com>
Here's an example:
#include <ffi.h>
#include <stdio.h>
int main (void)
{
ffi_cif cif;
void *args[4];
ffi_type *arg_types[3];
char *format = "%.5g, %d\n";
double doubleArg = 3.14159;
signed int sintArg = 7;
ffi_arg res = 0;
arg_types[0] = &ffi_type_pointer;
arg_types[1] = &ffi_type_double;
arg_types[2] = &ffi_type_sint;
arg_types[3] = NULL;
/* This printf call is variadic */
ffi_prep_cif_var(&cif, FFI_DEFAULT_ABI, 1, 3, &ffi_type_sint, arg_types);
args[0] = &format;
args[1] = &doubleArg;
args[2] = &sintArg;
args[3] = NULL;
ffi_call(&cif, FFI_FN(printf), &res, args);
return 0;
}
On Thu, Mar 18, 2021 at 10:04 AM ShaJunxing via Libffi-discuss <
libffi-discuss@sourceware.org> wrote:
> 'printf' not only has variable length arguments (maximum length is
> unlimited?), but also each argument type may be different. I searched
> the whole Internet but still found nothing, anybody help? thank you very
> much.
>
>
>
next prev parent reply other threads:[~2021-03-18 15:25 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-18 14:04 ShaJunxing
2021-03-18 15:25 ` Anthony Green [this message]
2021-03-19 2:08 ` ShaJunxing
2021-03-19 2:36 ` Kaz Kylheku (libffi)
2021-03-19 3:09 ` ShaJunxing
2021-03-19 10:13 ` Andrew Haley
2021-03-19 11:01 ` Anthony Green
2021-03-19 11:43 ` Andrew Haley
2021-03-20 22:40 ` Anthony Green
2021-03-20 23:56 ` Anthony Green
2021-03-22 10:36 ` Andrew Haley
2021-03-19 11:26 ` Jarkko Hietaniemi
2021-03-19 11:33 ` Anthony Green
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