Question

在我的上一个应用程序中，我有很多错误检查行，如：

if (something != 0) {
    perror("something error");
    exit(-1);
}

我的问题是，如何创建一个宏来使其像单行一样：

if (something != 0)
    PR("something error", -1);

Answer 1

通常，当呼叫系统出现故障时，我们会返回值EXIT_FAILURE，但您可以更改此代码以获得所需内容。

#define FOO(s) {\
        perror((s));\
        exit(EXIT_FAILURE); }

Answer 2

我认为有更好的方法可以解决它。

A）perror（）和exit（）

首先要记住的是perror()使用errno变量来打印邮件。因此，在您的简单情况下，如果未设置errno，则perror()会在字符串的末尾添加: Success\n，这可能会让您感到困惑，具体取决于您的消息。解决这个问题的一种方法是：

#include <errno.h>
#define PR(s, e) {errno=(e); perror((s)); exit((e)); }

然后

if(something != 0)
  PR("some error msg", 1);

注意：肯定1而不是-1作为错误代码。更多关于那个轰鸣声。

B）错误（）

更好的方法是使用error()消息。它有你想要的一切，不需要宏：

#include <error.h>

和

if(something != 0)
  error(1, YOURERRORCODE, "some error msg");

error(arg1, arg2, arg3, ...)函数的定义：

arg1：如果为0，程序将不会退出。任何其他值都会导致退出该值（最多255）。
arg2：错误代码。见下文。
arg3：包含自定义消息的字符串。它可以格式化为printf()消息，然后使用arg4, ...

注意：

退出代码范围：exit(e)的错误代码应仅在[0, 255]范围内。通常，0表示成功，1表示255表示错误代码。但是请注意，如果数字高于module，那么shell会255，这意味着如果您尝试exit(256)或exit(512)，您将获得代码0 （为了成功），或者例如exit(257)为您提供错误代码1，依此类推。
错误消息：查看所有错误消息，不要使用幻数，而是使用正确的错误代码设置{{1} }。

错误代码消息如下。值不 POSIX定义。建议仅使用 MACROS 。

errno

在某些较旧的系统中，这些错误代码不是别名，而是：

#define EPERM 1 /* Operation not permitted */
#define ENOENT 2 /* No such file or directory */
#define ESRCH 3 /* No such process */
#define EINTR 4 /* Interrupted system call */
#define EIO 5 /* I/O error */
#define ENXIO 6 /* No such device or address */
#define E2BIG 7 /* Argument list too long */
#define ENOEXEC 8 /* Exec format error */
#define EBADF 9 /* Bad file number */
#define ECHILD 10 /* No child processes */
#define EAGAIN 11 /* Try again */
#define ENOMEM 12 /* Out of memory */
#define EACCES 13 /* Permission denied */
#define EFAULT 14 /* Bad address */
#define ENOTBLK 15 /* Block device required */
#define EBUSY 16 /* Device or resource busy */
#define EEXIST 17 /* File exists */
#define EXDEV 18 /* Cross-device link */
#define ENODEV 19 /* No such device */
#define ENOTDIR 20 /* Not a directory */
#define EISDIR 21 /* Is a directory */
#define EINVAL 22 /* Invalid argument */
#define ENFILE 23 /* File table overflow */
#define EMFILE 24 /* Too many open files */
#define ENOTTY 25 /* Not a typewriter */
#define ETXTBSY 26 /* Text file busy */
#define EFBIG 27 /* File too large */
#define ENOSPC 28 /* No space left on device */
#define ESPIPE 29 /* Illegal seek */
#define EROFS 30 /* Read-only file system */
#define EMLINK 31 /* Too many links */
#define EPIPE 32 /* Broken pipe */
#define EDOM 33 /* Math argument out of domain of function */
#define ERANGE 34 /* Math result not representable */
#define EDEADLK 35 /* Resource deadlock would occur */
#define ENAMETOOLONG 36 /* File name too long */
#define ENOLCK 37 /* No record locks available */
#define ENOSYS 38 /* Invalid system call number */
#define ENOTEMPTY 39 /* Directory not empty */
#define ELOOP 40 /* Too many symbolic links encountered */

#define ENOMSG 42 /* No message of desired type */
#define EIDRM 43 /* Identifier removed */
#define ECHRNG 44 /* Channel number out of range */
#define EL2NSYNC 45 /* Level 2 not synchronized */
#define EL3HLT 46 /* Level 3 halted */
#define EL3RST 47 /* Level 3 reset */
#define ELNRNG 48 /* Link number out of range */
#define EUNATCH 49 /* Protocol driver not attached */
#define ENOCSI 50 /* No CSI structure available */
#define EL2HLT 51 /* Level 2 halted */
#define EBADE 52 /* Invalid exchange */
#define EBADR 53 /* Invalid request descriptor */
#define EXFULL 54 /* Exchange full */
#define ENOANO 55 /* No anode */
#define EBADRQC 56 /* Invalid request code */
#define EBADSLT 57 /* Invalid slot */

#define EBFONT 59 /* Bad font file format */
#define ENOSTR 60 /* Device not a stream */
#define ENODATA 61 /* No data available */
#define ETIME 62 /* Timer expired */
#define ENOSR 63 /* Out of streams resources */
#define ENONET 64 /* Machine is not on the network */
#define ENOPKG 65 /* Package not installed */
#define EREMOTE 66 /* Object is remote */
#define ENOLINK 67 /* Link has been severed */
#define EADV 68 /* Advertise error */
#define ESRMNT 69 /* Srmount error */
#define ECOMM 70 /* Communication error on send */
#define EPROTO 71 /* Protocol error */
#define EMULTIHOP 72 /* Multihop attempted */
#define EDOTDOT 73 /* RFS specific error */
#define EBADMSG 74 /* Not a data message */
#define EOVERFLOW 75 /* Value too large for defined data type */
#define ENOTUNIQ 76 /* Name not unique on network */
#define EBADFD 77 /* File descriptor in bad state */
#define EREMCHG 78 /* Remote address changed */
#define ELIBACC 79 /* Can not access a needed shared library */
#define ELIBBAD 80 /* Accessing a corrupted shared library */
#define ELIBSCN 81 /* .lib section in a.out corrupted */
#define ELIBMAX 82 /* Attempting to link in too many shared libraries */
#define ELIBEXEC 83 /* Cannot exec a shared library directly */
#define EILSEQ 84 /* Illegal byte sequence */
#define ERESTART 85 /* Interrupted system call should be restarted */
#define ESTRPIPE 86 /* Streams pipe error */
#define EUSERS 87 /* Too many users */
#define ENOTSOCK 88 /* Socket operation on non-socket */
#define EDESTADDRREQ 89 /* Destination address required */
#define EMSGSIZE 90 /* Message too long */
#define EPROTOTYPE 91 /* Protocol wrong type for socket */
#define ENOPROTOOPT 92 /* Protocol not available */
#define EPROTONOSUPPORT 93 /* Protocol not supported */
#define ESOCKTNOSUPPORT 94 /* Socket type not supported */
#define EOPNOTSUPP 95 /* Operation not supported on transport endpoint */
#define EPFNOSUPPORT 96 /* Protocol family not supported */
#define EAFNOSUPPORT 97 /* Address family not supported by protocol */
#define EADDRINUSE 98 /* Address already in use */
#define EADDRNOTAVAIL 99 /* Cannot assign requested address */
#define ENETDOWN 100 /* Network is down */
#define ENETUNREACH 101 /* Network is unreachable */
#define ENETRESET 102 /* Network dropped connection because of reset */
#define ECONNABORTED 103 /* Software caused connection abort */
#define ECONNRESET 104 /* Connection reset by peer */
#define ENOBUFS 105 /* No buffer space available */
#define EISCONN 106 /* Transport endpoint is already connected */
#define ENOTCONN 107 /* Transport endpoint is not connected */
#define ESHUTDOWN 108 /* Cannot send after transport endpoint shutdown */
#define ETOOMANYREFS 109 /* Too many references: cannot splice */
#define ETIMEDOUT 110 /* Connection timed out */
#define ECONNREFUSED 111 /* Connection refused */
#define EHOSTDOWN 112 /* Host is down */
#define EHOSTUNREACH 113 /* No route to host */
#define EALREADY 114 /* Operation already in progress */
#define EINPROGRESS 115 /* Operation now in progress */
#define ESTALE 116 /* Stale file handle */
#define EUCLEAN 117 /* Structure needs cleaning */
#define ENOTNAM 118 /* Not a XENIX named type file */
#define ENAVAIL 119 /* No XENIX semaphores available */
#define EISNAM 120 /* Is a named type file */
#define EREMOTEIO 121 /* Remote I/O error */
#define EDQUOT 122 /* Quota exceeded */
#define ENOMEDIUM 123 /* No medium found */
#define EMEDIUMTYPE 124 /* Wrong medium type */
#define ECANCELED 125 /* Operation Canceled */
#define ENOKEY 126 /* Required key not available */
#define EKEYEXPIRED 127 /* Key has expired */
#define EKEYREVOKED 128 /* Key has been revoked */
#define EKEYREJECTED 129 /* Key was rejected by service */
#define EOWNERDEAD 130 /* Owner died */
#define ENOTRECOVERABLE 131 /* State not recoverable */
#define ERFKILL 132 /* Operation not possible due to RF-kill */
#define EHWPOISON 133 /* Memory page has hardware error */

#define EWOULDBLOCK EAGAIN /* 11/41 Try again / Operation would block */
#define EDEADLOCK EDEADLK /* 35/58 Resource/File deadlock error */
#define ENOTSUP EOPNOTSUPP /* 95 Operation not supported on transport endpoint */

"Unknown errors": 41, 58, 134-255

但#define EWOULDBLOCK 41 /* Operation would block */ #define EDEADLOCK 58 /* File locking deadlock error */只是一个别名。

上面列表的草稿可以由您自己的机器使用bash命令生成：

ENOTSUP

文件（Debian Stretch 9）：

$ find /usr/include/ -name "errno*.h" -exec grep -HIe "define\s*E" {} \; | cut -d"#" -f2 | tr "\t" " " | tr -s " " | sed 's/^ //' | sed 's/^/#/' | sort -nk3 > errorcodes.txt

参考文献：

PS。上面的答案是可以的，但我更愿意使用$ find /usr/include/ -name "errno*.h" /usr/include/asm-generic/errno-base.h /usr/include/asm-generic/errno.h /usr/include/errno.h /usr/include/linux/errno.h /usr/include/x86_64-linux-gnu/bits/errno.h /usr/include/x86_64-linux-gnu/sys/errno.h /usr/include/x86_64-linux-gnu/asm/errno.h /usr/include/sys/errno.h。始终尝试使用标准库中已经完成的操作。避免重新发明轮子。

具有退出值宏的perror

2 个答案:

A）perror（）和exit（）

B）错误（）

注意：