Re: [PATCH] tools: Use fputc() calls in some functions

Re: [PATCH] tools: Use fputc() calls in some functions

[Andi Kleen]

On Thu, Jul 23, 2026 at 12:25:25PM +0200, Markus Elfring wrote:
> From: Markus Elfring <elfring@users.sourceforge.net>
> Date: Thu, 23 Jul 2026 11:13:30 +0200
> Subject: [PATCH] tools: Use fputc() calls in some functions
> MIME-Version: 1.0
> Content-Type: text/plain; charset=UTF-8
> Content-Transfer-Encoding: 8bit
> 
> Single characters should occasionally be transferred into the output.
> Thus use the corresponding function “fputc” (or even “putchar”).
> 
> The source code was transformed by using the Coccinelle software.

gcc already does this transformation automatically.

Re: [PATCH] tools: Use fputc() calls in some functions

[Steven Rostedt]

On Thu, 23 Jul 2026 06:47:00 -0700
Andi Kleen <ak@linux.intel.com> wrote:

> > The source code was transformed by using the Coccinelle software.  
> 
> gcc already does this transformation automatically.

Yep, I showed this in my talk[1] that looked at what printf("Hello World!")
does. Doing an objdump of:

#include <stdio.h>

int main(void) {
	printf("Hello World!\n");
	return 0;
}

has:

0000000000001139 <main>:
    1139:       55                      push   %rbp
    113a:       48 89 e5                mov    %rsp,%rbp
    113d:       48 8d 05 c0 0e 00 00    lea    0xec0(%rip),%rax        # 2004 <_IO_stdin_used+0x4>
    1144:       48 89 c7                mov    %rax,%rdi
    1147:       e8 e4 fe ff ff          call   1030 <puts@plt>  <<<--- puts and not printf
    114c:       b8 00 00 00 00          mov    $0x0,%eax
    1151:       5d                      pop    %rbp
    1152:       c3                      ret

-- Steve

[1] https://www.youtube.com/watch?v=JRyrhsx-L5Y