#define NULL ((void *)0)
typedef unsigned long size_t; // Customize by platform.
typedef long intptr_t;
typedef unsigned long uintptr_t;
typedef long scalar_t__; // Either arithmetic or pointer type.
/* By default, we understand bool (as a convenience). */
typedef int bool;
#define false 0
#define true 1

/* Forward declarations */
typedef struct TYPE_2__ TYPE_1__;

/* Type definitions */
struct sockaddr_in {
  int /*<<< orphan*/ sin_addr;
};
struct TYPE_2__ {
  int /*<<< orphan*/ sa_family;
};
struct ifreq {
  TYPE_1__ ifr_addr;
  int /*<<< orphan*/ ifr_name;
};

/* Variables and functions */
int /*<<< orphan*/ AF_INET;
scalar_t__ IFNAMSIZ;
int /*<<< orphan*/ SIOCGIFADDR;
int /*<<< orphan*/ SOCK_DGRAM;
int /*<<< orphan*/ close(int);
char *inet_ntoa(int /*<<< orphan*/);
int /*<<< orphan*/ ioctl(int, int /*<<< orphan*/, struct ifreq *);
int /*<<< orphan*/ printf(char *, char *);
int socket(int /*<<< orphan*/, int /*<<< orphan*/, int /*<<< orphan*/);
int /*<<< orphan*/ strncpy(int /*<<< orphan*/, char *, scalar_t__);
int main(int argc, char *argv[]) {
  int fd;
  struct ifreq ifr;
  fd = socket(AF_INET, SOCK_DGRAM, 0);
  ifr.ifr_addr.sa_family = AF_INET;
  strncpy(ifr.ifr_name, "eth0", IFNAMSIZ - 1);
  ioctl(fd, SIOCGIFADDR, &ifr);
  close(fd);
  printf("%s\n", inet_ntoa(((struct sockaddr_in *)&ifr.ifr_addr)->sin_addr));
  return 0;
}


x86 assembly (clang, -O0):
<main>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
movl   $0x0,-0x4(%rbp)
mov    %edi,-0x8(%rbp)
mov    %rsi,-0x10(%rbp)
mov    0x2e63(%rip),%rax
mov    (%rax),%edi
mov    0x2e52(%rip),%rax
mov    (%rax),%esi
xor    %edx,%edx
call   1080 <socket@plt>
mov    %eax,-0x14(%rbp)
mov    0x2e47(%rip),%rax
mov    (%rax),%eax
mov    %eax,-0x20(%rbp)
mov    -0x1c(%rbp),%edi
mov    0x2e20(%rip),%rax
mov    (%rax),%rdx
sub    $0x1,%rdx
lea    0xe4a(%rip),%rsi
call   1030 <strncpy@plt>
mov    -0x14(%rbp),%edi
mov    0x2e23(%rip),%rax
mov    (%rax),%esi
lea    -0x20(%rbp),%rdx
call   1060 <ioctl@plt>
mov    -0x14(%rbp),%edi
call   1070 <close@plt>
mov    -0x20(%rbp),%edi
call   1040 <inet_ntoa@plt>
mov    %rax,%rsi
lea    0xe1b(%rip),%rdi
call   1050 <printf@plt>
xor    %eax,%eax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<main>:
push   %r14
push   %rbx
push   %rax
mov    0x2e75(%rip),%r14
mov    (%r14),%edi
mov    0x2e63(%rip),%rax
mov    (%rax),%esi
xor    %edx,%edx
call   1080 <socket@plt>
mov    %eax,%ebx
mov    (%r14),%eax
mov    %eax,(%rsp)
mov    0x2e3b(%rip),%rax
mov    (%rax),%rdx
add    $0xffffffffffffffff,%rdx
lea    0xe65(%rip),%rsi
call   1030 <strncpy@plt>
mov    0x2e41(%rip),%rax
mov    (%rax),%esi
mov    %rsp,%rdx
mov    %ebx,%edi
call   1060 <ioctl@plt>
mov    %ebx,%edi
call   1070 <close@plt>
mov    (%rsp),%edi
call   1040 <inet_ntoa@plt>
lea    0xe3c(%rip),%rdi
mov    %rax,%rsi
call   1050 <printf@plt>
xor    %eax,%eax
add    $0x8,%rsp
pop    %rbx
pop    %r14
ret

LLVM IR (-O0):
%struct.ifreq = type { %struct.TYPE_2__, i32 }
%struct.TYPE_2__ = type { i32 }
%struct.sockaddr_in = type { i32 }
@AF_INET = global i32 0
@SOCK_DGRAM = global i32 0
@.str = [5 x i8] c"eth0\00"
@IFNAMSIZ = global i64 0
@SIOCGIFADDR = global i32 0
@.str.1 = [4 x i8] c"%s\0A\00"
define i32 @main(i32 %0, i8** %1) {
%3 = alloca i32
%4 = alloca i32
%5 = alloca i8**
%6 = alloca i32
%7 = alloca %struct.ifreq
store i32 0, i32* %3
store i32 %0, i32* %4
store i8** %1, i8*** %5
%8 = load i32, i32* @AF_INET
%9 = load i32, i32* @SOCK_DGRAM
%10 = call i32 @socket(i32 %8, i32 %9, i32 0)
store i32 %10, i32* %6
%11 = load i32, i32* @AF_INET
%12 = getelementptr inbounds %struct.ifreq, %struct.ifreq* %7, i32 0, i32 0
%13 = getelementptr inbounds %struct.TYPE_2__, %struct.TYPE_2__* %12, i32 0, i32 0
store i32 %11, i32* %13
%14 = getelementptr inbounds %struct.ifreq, %struct.ifreq* %7, i32 0, i32 1
%15 = load i32, i32* %14
%16 = load i64, i64* @IFNAMSIZ
%17 = sub nsw i64 %16, 1
%18 = call i32 @strncpy(i32 %15, i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str, i64 0, i64 0), i64 %17)
%19 = load i32, i32* %6
%20 = load i32, i32* @SIOCGIFADDR
%21 = call i32 @ioctl(i32 %19, i32 %20, %struct.ifreq* %7)
%22 = load i32, i32* %6
%23 = call i32 @close(i32 %22)
%24 = getelementptr inbounds %struct.ifreq, %struct.ifreq* %7, i32 0, i32 0
%25 = bitcast %struct.TYPE_2__* %24 to %struct.sockaddr_in*
%26 = getelementptr inbounds %struct.sockaddr_in, %struct.sockaddr_in* %25, i32 0, i32 0
%27 = load i32, i32* %26
%28 = call i8* @inet_ntoa(i32 %27)
%29 = call i32 @printf(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.1, i64 0, i64 0), i8* %28)
ret i32 0
}

LLVM IR (-O2):
%struct.ifreq = type { %struct.TYPE_2__, i32 }
%struct.TYPE_2__ = type { i32 }
@AF_INET = global i32 0
@SOCK_DGRAM = global i32 0
@.str = [5 x i8] c"eth0\00"
@IFNAMSIZ = global i64 0
@SIOCGIFADDR = global i32 0
@.str.1 = [4 x i8] c"%s\0A\00"
define i32 @main(i32 %0, i8** nocapture readnone %1) {
%3 = alloca %struct.ifreq
%4 = bitcast %struct.ifreq* %3 to i8*
%5 = load i32, i32* @AF_INET
%6 = load i32, i32* @SOCK_DGRAM
%7 = tail call i32 @socket(i32 %5, i32 %6, i32 0)
%8 = load i32, i32* @AF_INET
%9 = getelementptr inbounds %struct.ifreq, %struct.ifreq* %3, i64 0, i32 0, i32 0
store i32 %8, i32* %9
%10 = load i64, i64* @IFNAMSIZ
%11 = add nsw i64 %10, -1
%12 = tail call i32 @strncpy(i32 undef, i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str, i64 0, i64 0), i64 %11)
%13 = load i32, i32* @SIOCGIFADDR
%14 = call i32 @ioctl(i32 %7, i32 %13, %struct.ifreq* %3)
%15 = call i32 @close(i32 %7)
%16 = load i32, i32* %9
%17 = call i8* @inet_ntoa(i32 %16)
%18 = call i32 @printf(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.1, i64 0, i64 0), i8* %17)
ret i32 0
}