#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*/ ssize_t;

/* Variables and functions */
int /*<<< orphan*/ O_WRONLY;
int /*<<< orphan*/ close(int);
int /*<<< orphan*/ fprintf(int /*<<< orphan*/, char *);
int open(char *, int /*<<< orphan*/);
int /*<<< orphan*/ snprintf(char *, int, char *, int);
int /*<<< orphan*/ stderr;
int /*<<< orphan*/ write(int, char *, int /*<<< orphan*/);
int GPIOExport(int pin) {
  char buffer[3];
  ssize_t bytes_written;
  int fd;
  fd = open("/sys/class/gpio/export", O_WRONLY);
  if (fd == -1) {
    fprintf(stderr, "Failed to open export for writing.\n");
    return (-1);
  }
  bytes_written = snprintf(buffer, 3, "%d", pin);
  write(fd, buffer, bytes_written);
  close(fd);
  return (0);
}


x86 assembly (clang, -O0):
<GPIOExport>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
mov    %edi,-0x8(%rbp)
mov    0x2e6e(%rip),%rax
mov    (%rax),%esi
lea    0xe95(%rip),%rdi
call   1070 <open@plt>
mov    %eax,-0x14(%rbp)
cmpl   $0xffffffff,-0x14(%rbp)
jne    119e <GPIOExport+0x4e>
mov    0x2e5c(%rip),%rax
mov    (%rax),%edi
lea    0xe8a(%rip),%rsi
call   1060 <fprintf@plt>
movl   $0xffffffff,-0x4(%rbp)
jmp    11d7 <GPIOExport+0x87>
lea    -0xb(%rbp),%rdi
mov    -0x8(%rbp),%ecx
mov    $0x3,%esi
lea    0xe8a(%rip),%rdx
call   1040 <snprintf@plt>
mov    %eax,-0x10(%rbp)
mov    -0x14(%rbp),%edi
lea    -0xb(%rbp),%rsi
mov    -0x10(%rbp),%edx
call   1030 <write@plt>
mov    -0x14(%rbp),%edi
call   1050 <close@plt>
movl   $0x0,-0x4(%rbp)
mov    -0x4(%rbp),%eax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<GPIOExport>:
push   %rbp
push   %r14
push   %rbx
sub    $0x10,%rsp
mov    %edi,%ebp
mov    0x2e6f(%rip),%rax
mov    (%rax),%esi
lea    0xe96(%rip),%rdi
call   1070 <open@plt>
cmp    $0xffffffff,%eax
je     11a8 <GPIOExport+0x58>
mov    %eax,%ebx
lea    0xebe(%rip),%rdx
lea    0xd(%rsp),%r14
mov    %r14,%rdi
mov    $0x3,%esi
mov    %ebp,%ecx
call   1040 <snprintf@plt>
mov    %ebx,%edi
mov    %r14,%rsi
mov    %eax,%edx
call   1030 <write@plt>
mov    %ebx,%edi
call   1050 <close@plt>
xor    %eax,%eax
jmp    11c2 <GPIOExport+0x72>
mov    0x2e31(%rip),%rax
mov    (%rax),%edi
lea    0xe5f(%rip),%rsi
call   1060 <fprintf@plt>
mov    $0xffffffff,%eax
add    $0x10,%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
@stderr = global i32 0
@.str.1 = [36 x i8] c"Failed to open export for writing.\0A\00"
@.str.2 = [3 x i8] c"%d\00"
define i32 @GPIOExport(i32 %0) {
%2 = alloca i32
%3 = alloca i32
%4 = alloca [3 x i8]
%5 = alloca i32
%6 = alloca i32
store i32 %0, i32* %3
%7 = load i32, i32* @O_WRONLY
%8 = call i32 @open(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @.str, i64 0, i64 0), i32 %7)
store i32 %8, i32* %6
%9 = load i32, i32* %6
%10 = icmp eq i32 %9, -1
br i1 %10, label %11, label %14
11: ; preds = %1
%12 = load i32, i32* @stderr
%13 = call i32 @fprintf(i32 %12, i8* getelementptr inbounds ([36 x i8], [36 x i8]* @.str.1, i64 0, i64 0))
store i32 -1, i32* %2
br label %24
14: ; preds = %1
%15 = getelementptr inbounds [3 x i8], [3 x i8]* %4, i64 0, i64 0
%16 = load i32, i32* %3
%17 = call i32 @snprintf(i8* %15, i32 3, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.2, i64 0, i64 0), i32 %16)
store i32 %17, i32* %5
%18 = load i32, i32* %6
%19 = getelementptr inbounds [3 x i8], [3 x i8]* %4, i64 0, i64 0
%20 = load i32, i32* %5
%21 = call i32 @write(i32 %18, i8* %19, i32 %20)
%22 = load i32, i32* %6
%23 = call i32 @close(i32 %22)
store i32 0, i32* %2
br label %24
24: ; preds = %14, %11
%25 = load i32, i32* %2
ret i32 %25
}

LLVM IR (-O2):
@.str = [23 x i8] c"/sys/class/gpio/export\00"
@O_WRONLY = global i32 0
@stderr = global i32 0
@.str.1 = [36 x i8] c"Failed to open export for writing.\0A\00"
@.str.2 = [3 x i8] c"%d\00"
define i32 @GPIOExport(i32 %0) {
%2 = alloca [3 x i8]
%3 = getelementptr inbounds [3 x i8], [3 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 eq i32 %5, -1
br i1 %6, label %7, label %10
7: ; preds = %1
%8 = load i32, i32* @stderr
%9 = tail call i32 @fprintf(i32 %8, i8* getelementptr inbounds ([36 x i8], [36 x i8]* @.str.1, i64 0, i64 0))
br label %14
10: ; preds = %1
%11 = call i32 @snprintf(i8* %3, i32 3, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.2, i64 0, i64 0), i32 %0)
%12 = call i32 @write(i32 %5, i8* %3, i32 %11)
%13 = call i32 @close(i32 %5)
br label %14
14: ; preds = %10, %7
%15 = phi i32 [ -1, %7 ], [ 0, %10 ]
ret i32 %15
}