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

Steven Rostedt <[email protected]> Thu, 23 Jul 2026 10:33:36 -0400
Newsgroups dev.linux.lists.acpica-devel,dev.linux.lists.mptcp,dev.linux.lists.virtualization,org.kernel.vger.bpf,org.kernel.vger.kernel-janitors,org.kernel.vger.kvm,org.kernel.vger.linux-acpi,org.kernel.vger.linux-gpio,org.kernel.vger.linux-kernel,org.kernel.vger.linux-kselftest,org.kernel.vger.linux-perf-users,org.kernel.vger.linux-pm,org.kernel.vger.linux-trace-kernel,org.kernel.vger.netdev,org.kernel.vger.platform-driver-x86,org.kvack.linux-mm,org.ozlabs.lists.linuxppc-dev
Message-ID <[email protected]>
On Thu, 23 Jul 2026 06:47:00 -0700
Andi Kleen <[email protected]> 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