#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 */

/* Type definitions */
typedef int /*<<< orphan*/ buf;

/* Variables and functions */
int /*<<< orphan*/ O_WRONLY;
int /*<<< orphan*/ close(int);
int /*<<< orphan*/ error_exit(char *);
int open(char *, int /*<<< orphan*/);
int snprintf(char *, int, char *, unsigned int);
int /*<<< orphan*/ write(int, char *, int);
int gpio_export(unsigned int gpio) {
  int fd, len;
  char buf[64];
  fd = open("/sys/class/gpio"
            "/export",
            O_WRONLY);
  if (fd < 0)
    error_exit("gpio/export");
  len = snprintf(buf, sizeof(buf), "%d", gpio);
  write(fd, buf, len);
  close(fd);
  return 0;
}


x86 assembly (clang, -O0):
<gpio_export>:
push   %rbp
mov    %rsp,%rbp
sub    $0x50,%rsp
mov    %edi,-0x4(%rbp)
mov    0x2e76(%rip),%rax
mov    (%rax),%esi
lea    0xe95(%rip),%rdi
call   1070 <open@plt>
mov    %eax,-0x8(%rbp)
cmpl   $0x0,-0x8(%rbp)
jge    1189 <gpio_export+0x39>
lea    0xe87(%rip),%rdi
call   1060 <error_exit@plt>
lea    -0x50(%rbp),%rdi
mov    -0x4(%rbp),%ecx
mov    $0x40,%esi
lea    0xe7b(%rip),%rdx
call   1040 <snprintf@plt>
mov    %eax,-0xc(%rbp)
mov    -0x8(%rbp),%edi
lea    -0x50(%rbp),%rsi
mov    -0xc(%rbp),%edx
call   1030 <write@plt>
mov    -0x8(%rbp),%edi
call   1050 <close@plt>
xor    %eax,%eax
add    $0x50,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<gpio_export>:
push   %rbp
push   %r14
push   %rbx
sub    $0x40,%rsp
mov    %edi,%r14d
mov    0x2e76(%rip),%rax
mov    (%rax),%esi
lea    0xe95(%rip),%rdi
call   1070 <open@plt>
mov    %eax,%ebx
test   %eax,%eax
jns    1182 <gpio_export+0x32>
lea    0xe8e(%rip),%rdi
call   1060 <error_exit@plt>
lea    0xe8e(%rip),%rdx
mov    %rsp,%rbp
mov    %rbp,%rdi
mov    $0x40,%esi
mov    %r14d,%ecx
call   1040 <snprintf@plt>
mov    %ebx,%edi
mov    %rbp,%rsi
mov    %eax,%edx
call   1030 <write@plt>
mov    %ebx,%edi
call   1050 <close@plt>
xor    %eax,%eax
add    $0x40,%rsp
pop    %rbx
pop    %r14
pop    %rbp
ret

LLVM IR (-O0):
@.str = [23 x i8] c"/sys/class/gpio/export\00"
@O_WRONLY = global i32 0
@.str.1 = [12 x i8] c"gpio/export\00"
@.str.2 = [3 x i8] c"%d\00"
define i32 @gpio_export(i32 %0) {
%2 = alloca i32
%3 = alloca i32
%4 = alloca i32
%5 = alloca [64 x i8]
store i32 %0, i32* %2
%6 = load i32, i32* @O_WRONLY
%7 = call i32 @open(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @.str, i64 0, i64 0), i32 %6)
store i32 %7, i32* %3
%8 = load i32, i32* %3
%9 = icmp slt i32 %8, 0
br i1 %9, label %10, label %12
10: ; preds = %1
%11 = call i32 @error_exit(i8* getelementptr inbounds ([12 x i8], [12 x i8]* @.str.1, i64 0, i64 0))
br label %12
12: ; preds = %10, %1
%13 = getelementptr inbounds [64 x i8], [64 x i8]* %5, i64 0, i64 0
%14 = load i32, i32* %2
%15 = call i32 @snprintf(i8* %13, i32 64, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.2, i64 0, i64 0), i32 %14)
store i32 %15, i32* %4
%16 = load i32, i32* %3
%17 = getelementptr inbounds [64 x i8], [64 x i8]* %5, i64 0, i64 0
%18 = load i32, i32* %4
%19 = call i32 @write(i32 %16, i8* %17, i32 %18)
%20 = load i32, i32* %3
%21 = call i32 @close(i32 %20)
ret i32 0
}

LLVM IR (-O2):
@.str = [23 x i8] c"/sys/class/gpio/export\00"
@O_WRONLY = global i32 0
@.str.1 = [12 x i8] c"gpio/export\00"
@.str.2 = [3 x i8] c"%d\00"
define i32 @gpio_export(i32 %0) {
%2 = alloca [64 x i8]
%3 = getelementptr inbounds [64 x i8], [64 x i8]* %2, i64 0, i64 0
%4 = load i32, i32* @O_WRONLY
%5 = tail call i32 @open(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @.str, i64 0, i64 0), i32 %4)
%6 = icmp slt i32 %5, 0
br i1 %6, label %7, label %9
7: ; preds = %1
%8 = tail call i32 @error_exit(i8* getelementptr inbounds ([12 x i8], [12 x i8]* @.str.1, i64 0, i64 0))
br label %9
9: ; preds = %7, %1
%10 = call i32 @snprintf(i8* %3, i32 64, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.2, i64 0, i64 0), i32 %0)
%11 = call i32 @write(i32 %5, i8* %3, i32 %10)
%12 = call i32 @close(i32 %5)
ret i32 0
}