背景
errno.h是C 编程语言标准库中的头文件。它定义了使用符号errno (“错误号”的缩写)报告和检索错误情况的宏。经常需要用来在内核态用户态返回错误寻找,本文以供快速检索。
常用函数与用法
strerror 根据errno获取文件
比如:
FILE *file = fopen("non_file.txt", "r");
if (file == NULL) {
// 输出错误信息
printf("Error opening file: %s\n", strerror(errno));
return EXIT_FAILURE;
}
实战输出:
函数返回
某个地方执行事务可以直接用 return -Exxx
这里的Exxx就是下面的 errorno的宏定义, 比如return -EPERM;
表示没有权限
头文件
errno.h
对应关系
#define EPERM 1 /* Not super-user */
#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 /* Arg list too long */
#define ENOEXEC 8 /* Exec format error */
#define EBADF 9 /* Bad file number */
#define ECHILD 10 /* No children */
#define EAGAIN 11 /* No more processes */
#define ENOMEM 12 /* Not enough core */
#define EACCES 13 /* Permission denied */
#define EFAULT 14 /* Bad address */
#define ENOTBLK 15 /* Block device required */
#define EBUSY 16 /* Mount device 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 /* Too many open files in system */
#define EMFILE 24 /* Too many open files */
#define ENOTTY 25 /* Not a typewriter */
#define ETXTBSY 26 /* Text file busy */
#define EFBIG