![\"\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/10\/20261001032133-6abdd1bd0dc26.png\")
<\/p>\n\u00a0💁\u200d\u2642\ufe0f\u4e2a\u4eba\u4e3b\u9875：\u8fdb\u51fb\u7684\u8346\u68d8<\/p>\n
👇\u4f5c\u8005\u5176\u5b83\u4e13\u680f：<\/p>\n
\u300a\u6570\u636e\u7ed3\u6784\u4e0e\u7b97\u6cd5\u300b\u300a\u7b97\u6cd5\u300b\u300aC++\u8d77\u59cb\u4e4b\u8def\u300b\u300aLinux\u300b<\/p>\n
\u9996\u5148，\u5728windows\u4e2d\u662f\u6587\u4ef6\u7684\u4e1c\u897f，\u5728linux\u4e2d\u4e5f\u662f\u6587\u4ef6；\u5176\u6b21\u4e00\u4e9b\u5728windows\u4e2d\u4e0d\u662f\u6587\u4ef6\u7684\u4e1c\u897f，\u5982：\u8fdb\u7a0b\u3001\u78c1\u76d8\u3001\u663e\u793a\u5668\u3001\u952e\u76d8\u8fd9\u6837\u7684\u786c\u4ef6\u8bbe\u5907\u4e5f\u88ab\u62bd\u8c61\u6210\u4e86\u6587\u4ef6，\u53ef\u4ee5\u4f7f\u7528\u8bbf\u95ee\u6587\u4ef6\u7684\u65b9\u6cd5\u8bbf\u95ee\u5b83\u4eec\u83b7\u5f97\u4fe1\u606f；\u751a\u81f3\u7ba1\u9053\u4e5f\u662f\u6587\u4ef6；\u5c06\u6765\u7f51\u7edc\u7f16\u7a0b\u4e2d\u7684socket（\u5957\u63a5\u5b57）\u8fd9\u6837\u7684\u4e1c\u897f，\u4f7f\u7528\u7684\u63a5\u53e3\u8ddf\u6587\u4ef6\u63a5\u53e3\u4e5f\u662f\u4e00\u81f4\u7684\u3002<\/p>\n
\u8fd9\u6837\u505a\u6700\u660e\u663e\u7684\u597d\u5904\u662f，\u5f00\u53d1\u8005\u4ec5\u9700\u4f7f\u7528\u4e00\u5957API\u548c\u5f00\u53d1\u5de5\u5177，\u5373\u53ef\u8c03\u53d6Linux\u7cfb\u7edf\u4e2d\u7edd\u5927\u90e8\u5206\u7684\u8d44\u6e90\u3002\u4f8b：Linux\u4e2d\u51e0\u4e4e\u6240\u6709\u8bfb（\u8bfb\u6587\u4ef6，\u8bfb\u7cfb\u7edf\u72b6\u6001，\u8bfbPIPE）\u7684\u64cd\u4f5c\u90fd\u53ef\u4ee5\u7528read\u51fd\u6570\u8fdb\u884c；\u51e0\u4e4e\u6240\u6709（\u66f4\u6539\u6587\u4ef6，\u66f4\u6539\u7cfb\u7edf\u53c2\u6570，\u5199PIPE）\u7684\u64cd\u4f5c\u90fd\u53ef\u4ee5\u7528write\u51fd\u6570\u6765\u8fdb\u884c\u3002<\/p>\n
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struct file {
\n …
\n struct inode *f_inode; \/* cached value *\/
\n const struct file_operations *f_op;
\n …
\n atomic_long_t f_count; \/\/ \u8868\u2f70\u6253\u5f00\u2f42\u4ef6\u7684\u5f15\u2f64\u8ba1\u6570，\u5982\u679c\u6709\u591a\u4e2a\u2f42\u4ef6\u6307\u9488\u6307
\n\u5411\u5b83，\u5c31\u4f1a\u589e\u52a0f_count\u7684\u503c\u3002
\n unsigned int f_flags; \/\/ \u8868\u2f70\u6253\u5f00\u2f42\u4ef6\u7684\u6743\u9650
\n fmode_t f_mode; \/\/ \u8bbe\u7f6e\u5bf9\u2f42\u4ef6\u7684\u8bbf\u95ee\u6a21\u5f0f,\u4f8b\u5982：\u53ea\u8bfb，\u53ea\u5199\u7b49\u3002\u6240
\n\u6709\u7684\u6807\u5fd7\u5728\u5934\u2f42\u4ef6<fcntl.h> \u4e2d\u5b9a\u4e49
\n loff_t f_pos; \/\/ \u8868\u2f70\u5f53\u524d\u8bfb\u5199\u2f42\u4ef6\u7684\u4f4d\u7f6e
\n …
\n} __attribute__((aligned(4))); \/* lest something weird decides that 2 is OK
\n*\/ <\/p>\n
struct file\u4e2d\u7684f_op\u6307\u9488\u6307\u5411\u4e86\u4e00\u4e2afile_operations\u7ed3\u6784\u4f53，\u8fd9\u4e2a\u7ed3\u6784\u4f53\u4e2d\u7684\u6210\u5458\u9664\u4e86struct module* owner\u5176\u4f59\u90fd\u662f\u51fd\u6570\u6307\u9488\u3002\u8be5\u7ed3\u6784\u548cstruct file\u90fd\u5728fs.h\u4e0b<\/p>\n
truct file_operations {
\n struct module *owner;
\n \/\/\u6307\u5411\u62e5\u6709\u8be5\u6a21\u5757\u7684\u6307\u9488；
\n loff_t (*llseek) (struct file *, loff_t, int);
\n \/\/llseek \u2f45\u6cd5\u2f64\u4f5c\u6539\u53d8\u2f42\u4ef6\u4e2d\u7684\u5f53\u524d\u8bfb\/\u5199\u4f4d\u7f6e, \u5e76\u4e14\u65b0\u4f4d\u7f6e\u4f5c\u4e3a(\u6b63\u7684)\u8fd4\u56de\u503c.
\n ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);
\n \/\/\u2f64\u6765\u4ece\u8bbe\u5907\u4e2d\u83b7\u53d6\u6570\u636e. \u5728\u8fd9\u4e2a\u4f4d\u7f6e\u7684\u2f00\u4e2a\u7a7a\u6307\u9488\u5bfc\u81f4 read \u7cfb\u7edf\u8c03\u2f64\u4ee5 –
\nEINVAL("Invalid argument") \u5931\u8d25. \u2f00\u4e2a\u2fae\u8d1f\u8fd4\u56de\u503c\u4ee3\u8868\u4e86\u6210\u529f\u8bfb\u53d6\u7684\u5b57\u8282\u6570( \u8fd4\u56de\u503c\u662f\u2f00\u4e2a
\n"signed size" \u7c7b\u578b, \u5e38\u5e38\u662f\u2f6c\u6807\u5e73\u53f0\u672c\u5730\u7684\u6574\u6570\u7c7b\u578b).
\n ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
\n \/\/\u53d1\u9001\u6570\u636e\u7ed9\u8bbe\u5907. \u5982\u679c NULL, -EINVAL \u8fd4\u56de\u7ed9\u8c03\u2f64 write \u7cfb\u7edf\u8c03\u2f64\u7684\u7a0b\u5e8f. \u5982\u679c\u2fae\u8d1f,
\n\u8fd4\u56de\u503c\u4ee3\u8868\u6210\u529f\u5199\u7684\u5b57\u8282\u6570.
\n ssize_t (*aio_read) (struct kiocb *, const struct iovec *, unsigned long,
\nloff_t);
\n \/\/\u521d\u59cb\u5316\u2f00\u4e2a\u5f02\u6b65\u8bfb — \u53ef\u80fd\u5728\u51fd\u6570\u8fd4\u56de\u524d\u4e0d\u7ed3\u675f\u7684\u8bfb\u64cd\u4f5c.
\n ssize_t (*aio_write) (struct kiocb *, const struct iovec *, unsigned
\nlong, loff_t);
\n \/\/\u521d\u59cb\u5316\u8bbe\u5907\u4e0a\u7684\u2f00\u4e2a\u5f02\u6b65\u5199.
\n int (*readdir) (struct file *, void *, filldir_t);
\n \/\/\u5bf9\u4e8e\u8bbe\u5907\u2f42\u4ef6\u8fd9\u4e2a\u6210\u5458\u5e94\u5f53\u4e3a NULL; \u5b83\u2f64\u6765\u8bfb\u53d6\u2f6c\u5f55, \u5e76\u4e14\u4ec5\u5bf9**\u2f42\u4ef6\u7cfb\u7edf**\u6709\u2f64.
\n unsigned int (*poll) (struct file *, struct poll_table_struct *);
\n int (*ioctl) (struct inode *, struct file *, unsigned int, unsigned long);
\n long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
\n long (*compat_ioctl) (struct file *, unsigned int, unsigned long);
\n int (*mmap) (struct file *, struct vm_area_struct *);
\n \/\/mmap \u2f64\u6765\u8bf7\u6c42\u5c06\u8bbe\u5907\u5185\u5b58\u6620\u5c04\u5230\u8fdb\u7a0b\u7684\u5730\u5740\u7a7a\u95f4. \u5982\u679c\u8fd9\u4e2a\u2f45\u6cd5\u662f NULL, mmap \u7cfb\u7edf\u8c03\u2f64
\n\u8fd4\u56de -ENODEV.
\n int (*open) (struct inode *, struct file *);
\n \/\/\u6253\u5f00\u2f00\u4e2a\u2f42\u4ef6
\n int (*flush) (struct file *, fl_owner_t id);
\n \/\/flush \u64cd\u4f5c\u5728\u8fdb\u7a0b\u5173\u95ed\u5b83\u7684\u8bbe\u5907\u2f42\u4ef6\u63cf\u8ff0\u7b26\u7684\u62f7\u2ec9\u65f6\u8c03\u2f64;
\n int (*release) (struct inode *, struct file *);
\n \/\/\u5728\u2f42\u4ef6\u7ed3\u6784\u88ab\u91ca\u653e\u65f6\u5f15\u2f64\u8fd9\u4e2a\u64cd\u4f5c. \u5982\u540c open, release \u53ef\u4ee5\u4e3a NULL.
\n int (*fsync) (struct file *, struct dentry *, int datasync);
\n \/\/\u2f64\u2f3e\u8c03\u2f64\u6765\u5237\u65b0\u4efb\u4f55\u6302\u7740\u7684\u6570\u636e.
\n int (*aio_fsync) (struct kiocb *, int datasync);
\n int (*fasync) (int, struct file *, int);
\n int (*lock) (struct file *, int, struct file_lock *);
\n \/\/lock \u2f45\u6cd5\u2f64\u6765\u5b9e\u73b0\u2f42\u4ef6\u52a0\u9501; \u52a0\u9501\u5bf9\u5e38\u89c4\u2f42\u4ef6\u662f\u5fc5\u4e0d\u53ef\u5c11\u7684\u7279\u6027, \u4f46\u662f\u8bbe\u5907\u9a71\u52a8\u2f0f\u4e4e\u4ece\u4e0d\u5b9e
\n\u73b0\u5b83.
\n ssize_t (*sendpage) (struct file *, struct page *, int, size_t, loff_t *,
\nint);
\n unsigned long (*get_unmapped_area)(struct file *, unsigned long, unsigned
\n long, unsigned long, unsigned long);
\n int (*check_flags)(int);
\n int (*flock) (struct file *, int, struct file_lock *);
\n ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, loff_t
\n*, size_t, unsigned int);
\n ssize_t (*splice_read)(struct file *, loff_t *, struct pipe_inode_info *,
\nsize_t, unsigned int);
\n int (*setlease)(struct file *, long, struct file_lock **);
\n}; <\/p>\n
file_operation\u5c31\u662f\u628a\u7cfb\u7edf\u8c03\u7528\u548c\u9a71\u52a8\u7a0b\u5e8f\u5173\u8054\u8d77\u6765\u7684\u5173\u952e\u6570\u636e\u7ed3\u6784，\u8fd9\u4e2a\u7ed3\u6784\u7684\u6bcf\u4e00\u4e2a\u6210\u5458\u90fd\u5bf9\u5e94\u7740\u4e00\u4e2a\u7cfb\u7edf\u8c03\u7528\u3002\u8bfb\u53d6file_operation\u4e2d\u76f8\u5e94\u7684\u51fd\u6570\u6307\u9488，\u63a5\u7740\u628a\u63a7\u5236\u6743\u8f6c\u4ea4\u7ed9\u51fd\u6570，\u4ece\u800c\u5b8c\u6210Linux\u8bbe\u5907\u9a71\u52a8\u7a0b\u5e8f\u7684\u5de5\u4f5c\u3002<\/p>\n
<\/p>\n
\u4e0a\u56fe\u4e2d\u7684\u5916\u8bbe，\u6bcf\u4e2a\u8bbe\u5907\u90fd\u53ef\u4ee5\u6709\u81ea\u5df1\u7684read\u3001write，\u4f46\u4e00\u5b9a\u662f\u5bf9\u5e94\u7740\u4e0d\u540c\u7684\u64cd\u4f5c\u65b9\u6cd5\u3002\u4f46\u901a\u8fc7struct file\u4e0bfile_operation\u4e2d\u7684\u5404\u79cd\u51fd\u6570\u56de\u8c03，\u8ba9\u5f00\u53d1\u8005\u53ea\u7528file\u4fbf\u53ef\u8c03\u53d6Linux\u7cfb\u7edf\u4e2d\u7edd\u5927\u90e8\u5206\u7684\u8d44\u6e90\u3002<\/p>\n
\u7f13\u51b2\u533a\u662f\u5185\u5b58\u7a7a\u95f4\u7684\u4e00\u90e8\u5206\u3002\u5373\u5728\u5185\u5b58\u7a7a\u95f4\u9884\u7559\u4e86\u4e00\u5b9a\u7684\u5b58\u50a8\u7a7a\u95f4，\u8fd9\u4e9b\u5b58\u50a8\u7a7a\u95f4\u7528\u6765\u7f13\u51b2\u8f93\u5165\u6216\u8f93\u51fa\u7684\u6570\u636e，\u8fd9\u90e8\u5206\u9884\u7559\u7684\u7a7a\u95f4\u5c31\u53eb\u505a\u7f13\u51b2\u533a\u3002\u7f13\u51b2\u533a\u6839\u636e\u5176\u5bf9\u5e94\u7684\u662f\u8f93\u5165\u8bbe\u5907\u8fd8\u662f\u8f93\u51fa\u8bbe\u5907，\u5206\u4e3a\u8f93\u5165\u7f13\u51b2\u533a\u548c\u8f93\u51fa\u7f13\u51b2\u533a\u3002<\/p>\n
\u8bfb\u5199\u6587\u4ef6\u65f6，\u82e5\u4e0d\u4f1a\u5f00\u8f9f\u5bf9\u6587\u4ef6\u64cd\u4f5c\u7684\u7f13\u51b2\u533a，\u76f4\u63a5\u901a\u8fc7\u7cfb\u7edf\u8c03\u7528\u5bf9\u78c1\u76d8\u8fdb\u884c\u64cd\u4f5c（\u8bfb\u3001\u5199\u7b49），\u90a3\u4e48\u6bcf\u6b21\u5bf9\u6587\u4ef6\u8fdb\u884c\u4e00\u6b21\u8bfb\u5199\u64cd\u4f5c\u65f6，\u90fd\u9700\u8981\u4f7f\u7528\u8bfb\u5199\u7cfb\u7edf\u8c03\u7528\u6765\u5904\u7406\u6b64\u64cd\u4f5c，\u5373\u9700\u8981\u6267\u884c\u4e00\u6b21\u7cfb\u7edf\u8c03\u7528，\u6267\u884c\u4e00\u6b21\u7cfb\u7edf\u8c03\u7528\u5c06\u6d89\u53ca\u5230CPU\u72b6\u6001\u7684\u5207\u6362，\u5373\u4ece\u7528\u6237\u7a7a\u95f4\u5207\u6362\u5230\u5185\u6838\u7a7a\u95f4，\u5b9e\u73b0\u8fdb\u7a0b\u4e0a\u4e0b\u6587\u7684\u5207\u6362，\u8fd9\u5c06\u635f\u8017\u4e00\u5b9a\u7684CPU\u65f6\u95f4，\u9891\u7e41\u7684\u78c1\u76d8\u8bbf\u95ee\u5bf9\u7a0b\u5e8f\u7684\u6267\u884c\u6548\u7387\u9020\u6210\u5f88\u5927\u7684\u5f71\u54cd\u3002<\/p>\n
\u4e3a\u4e86\u51cf\u5c11\u4f7f\u7528\u7cfb\u7edf\u8c03\u7528\u7684\u6b21\u6570，\u63d0\u9ad8\u6548\u7387，\u6211\u4eec\u5c31\u53ef\u4ee5\u91c7\u7528\u7f13\u5b58\u673a\u5236\u3002\u6bd4\u5982：\u4ece\u78c1\u76d8\u4e2d\u53d6\u4fe1\u606f，\u53ef\u4ee5\u5728\u78c1\u76d8\u6587\u4ef6\u8fdb\u884c\u64cd\u4f5c\u65f6，\u53ef\u4ee5\u4e00\u6b21\u4ece\u6587\u4ef6\u4e2d\u8bfb\u51fa\u5927\u91cf\u7684\u6570\u636e\u5230\u7f13\u51b2\u533a\u4e2d，\u4ee5\u540e\u5bf9\u8fd9\u90e8\u5206\u7684\u8bbf\u95ee\u5c31\u4e0d\u9700\u8981\u518d\u4f7f\u7528\u7cfb\u7edf\u8c03\u7528\u4e86，\u7b49\u7f13\u51b2\u533a\u7684\u6570\u636e\u53d6\u5b8c\u540e\u518d\u53bb\u78c1\u76d8\u4e2d\u8bfb\u53d6，\u8fd9\u6837\u5c31\u53ef\u4ee5\u51cf\u5c11\u78c1\u76d8\u7684\u8bfb\u5199\u6b21\u6570，\u518d\u52a0\u4e0a\u8ba1\u7b97\u673a\u5bf9\u7f13\u51b2\u533a\u7684\u64cd\u4f5c\u5927\u5927\u5feb\u4e8e\u5bf9\u78c1\u76d8\u7684\u64cd\u4f5c，\u6545\u5e94\u7528\u7f13\u51b2\u533a\u53ef\u5927\u5927\u63d0\u9ad8\u8ba1\u7b97\u673a\u7684\u8fd0\u884c\u901f\u5ea6\u3002<\/p>\n
\u53c8\u5982：\u6211\u4eec\u4f7f\u7528\u6253\u5370\u673a\u6253\u5370\u6587\u6863，\u7531\u4e8e\u6253\u5370\u673a\u7684\u6253\u5370\u901f\u5ea6\u76f8\u5bf9\u8f83\u6162，\u53ef\u4ee5\u5148\u628a\u6587\u6863\u8f93\u51fa\u5230\u6253\u5370\u673a\u76f8\u5e94\u7684\u7f13\u51b2\u533a，\u6253\u5370\u673a\u518d\u81ea\u884c\u9010\u6b65\u6253\u5370，\u8fd9\u65f6CPU\u53ef\u4ee5\u5904\u7406\u5176\u5b83\u4e8b\u60c5\u3002\u53ef\u4ee5\u770b\u51fa，\u7f13\u51b2\u533a\u5c31\u662f\u4e00\u5757\u5185\u5b58\u533a，\u5b83\u7528\u518d\u8f93\u5165\u8f93\u51fa\u8bbe\u5907\u548cCPU\u4e4b\u95f4，\u7528\u6765\u7f13\u5b58\u6570\u636e\u3002\u5b83\u4f7f\u5f97\u4f4e\u901f\u7684\u8f93\u5165\u8f93\u51fa\u8bbe\u5907\u548c\u9ad8\u901f\u7684CPU\u80fd\u591f\u534f\u8c03\u5de5\u4f5c，\u907f\u514d\u4f4e\u901f\u7684\u8f93\u5165\u8f93\u51fa\u8bbe\u5907\u5360\u7528CPU，\u89e3\u653e\u51faCPU，\u4f7f\u5176\u80fd\u9ad8\u6548\u5de5\u4f5c\u3002<\/p>\n
\u6807\u51c6I\/O\u63d0\u4f9b\u4e863\u79cd\u7c7b\u578b\u7684\u7f13\u51b2\u533a<\/p>\n
\u25cf\u5168\u7f13\u51b2\u533a：\u8fd9\u79cd\u7f13\u5b58\u65b9\u5f0f\u8981\u6c42\u586b\u6ee1\u6574\u4e2a\u7f13\u51b2\u533a\u540e\u624d\u8fdb\u884cI\/O\u7cfb\u7edf\u8c03\u7528\u64cd\u4f5c\u3002\u5bf9\u4e8e\u78c1\u76d8\u6587\u4ef6\u7684\u64cd\u4f5c\u901a\u5e38\u4f7f\u7528\u5168\u7f13\u51b2\u7684\u65b9\u5f0f\u8bbf\u95ee\u3002<\/p>\n
\u25cf\u884c\u7f13\u51b2\u533a：\u5728\u884c\u7f13\u51b2\u60c5\u51b5\u4e0b，\u5f53\u8f93\u5165\u548c\u8f93\u51fa\u79cd\u9047\u5230\u6362\u884c\u7b26\u65f6，\u6807\u51c6I\/O\u5e93\u51fd\u6570\u5c06\u4f1a\u6267\u884c\u7cfb\u7edf\u8c03\u7528\u64cd\u4f5c\u3002\u5f53\u6240\u64cd\u4f5c\u7684\u6d41\u6d89\u53ca\u4e00\u4e2a\u7ec8\u7aef\u65f6（\u5982\u6807\u51c6\u8f93\u5165\u548c\u6807\u51c6\u8f93\u51fa），\u4f7f\u7528\u884c\u7f13\u51b2\u65b9\u5f0f\u3002\u56e0\u4e3a\u6807\u51c6I\/O\u5e93\u6bcf\u884c\u7684\u7f13\u51b2\u533a\u957f\u5ea6\u662f\u56fa\u5b9a\u7684，\u6240\u4ee5\u53ea\u8981\u586b\u6ee1\u4e86\u7f13\u51b2\u533a，\u5373\u4f7f\u8fd8\u6ca1\u6709\u9047\u5230\u6362\u884c\u7b26，\u4e5f\u4f1a\u6267\u884cI\/O\u7cfb\u7edf\u8c03\u7528\u64cd\u4f5c，\u9ed8\u8ba4\u884c\u7f13\u51b2\u533a\u7684\u5927\u5c0f\u662f1024\u3002<\/p>\n
\u25cf\u65e0\u7f13\u51b2\u533a：\u65e0\u7f13\u51b2\u533a\u662f\u6307\u6807\u51c6I\/O\u5e93\u4e0d\u5bf9\u5b57\u7b26\u8fdb\u884c\u7f13\u5b58，\u76f4\u63a5\u8c03\u7528\u7cfb\u7edf\u8c03\u7528\u3002\u6807\u51c6\u51fa\u9519\u6d41stderr\u901a\u5e38\u662f\u4e0d\u5e26\u7f13\u51b2\u533a\u7684，\u8fd9\u4f7f\u5f97\u51fa\u9519\u4fe1\u606f\u80fd\u591f\u5c3d\u5feb\u5730\u663e\u793a\u51fa\u6765\u3002<\/p>\n
\u9664\u4e86\u4e0a\u8ff0\u5217\u4e3e\u7684\u9ed8\u8ba4\u5237\u65b0\u65b9\u5f0f，\u4e0b\u5217\u7279\u6b8a\u60c5\u51b5\u4e5f\u4f1a\u5f15\u53d1\u7f13\u51b2\u533a\u7684\u5237\u65b0：<\/p>\n
1.\u7f13\u51b2\u533a\u6ee1\u65f6；<\/p>\n
2.\u6267\u884cflsuh\u8bed\u53e5；<\/p>\n
3.\u8fdb\u7a0b\u7ed3\u675f<\/p>\n
#include <stdio.h>
\n#include <string.h>
\n#include <sys\/types.h>
\n#include <sys\/stat.h>
\n#include <fcntl.h>
\n#include <unistd.h><\/p>\n
int main() {
\n close(1);
\n int fd = open("log.txt", O_WRONLY | O_CREAT | O_TRUNC, 0666);
\n if (fd < 0) {
\n perror("open");
\n return 0;
\n }
\n printf("hello world: %d\\\\n", fd);
\n close(fd);
\n return 0;
\n}<\/p>\n
\u8fd9\u6bb5\u4ee3\u7801\u7684\u672c\u610f\u662f\u5e94\u7528\u91cd\u5b9a\u5411\u601d\u7ef4，\u8ba9\u672c\u5e94\u6253\u5370\u5230\u663e\u793a\u5668\u4e0a\u7684\u5185\u5bb9\u5199\u5230\u201clog.txt\u201d\u6587\u4ef6\u4e2d，\u4f46\u5b9e\u9645\u4e0a，\u7a0b\u5e8f\u8fd0\u884c\u7ed3\u675f\u540e，\u6587\u4ef6\u4e2d\u5e76\u6ca1\u6709\u5199\u5165\u5185\u5bb9：<\/p>\n
[sjx@VM-8-12-centos buffer]$ .\/myfile
\n[sjx@VM-8-12-centos buffer]$ ls
\nlog.txt makefile myfile myfile.c
\n[sjx@VM-8-12-centos buffer]$ cat log.txt
\n[sjx@VM-8-12-centos buffer]$<\/p>\n
\u8fd9\u662f\u56e0\u4e3a\u6211\u4eec\u5c061\u53f7\u63cf\u8ff0\u7b26\u91cd\u5b9a\u5411\u5230\u78c1\u76d8\u6587\u4ef6\u540e，\u7f13\u51b2\u533a\u7684\u5237\u65b0\u65b9\u5f0f\u6210\u4e3a\u4e86\u5168\u7f13\u51b2\u3002\u800c\u5199\u5165\u7684\u5185\u5bb9\u5e76\u6ca1\u6709\u586b\u6ee1\u6574\u4e2a\u7f13\u51b2\u533a，\u5bfc\u81f4\u5e76\u4e0d\u4f1a\u5c06\u7f13\u51b2\u533a\u7684\u5185\u5bb9\u5237\u65b0\u5230\u78c1\u76d8\u6587\u4ef6\u4e2d\u3002\u53ef\u4ee5\u4f7f\u7528fflush\u5f3a\u5236\u5237\u65b0\u7f13\u51b2\u533a\u3002<\/p>\n
#include <stdio.h>
\n#include <string.h>
\n#include <sys\/types.h>
\n#include <sys\/stat.h>
\n#include <fcntl.h>
\n#include <unistd.h><\/p>\n
int main() {
\n close(1);
\n int fd = open("log.txt", O_WRONLY | O_CREAT | O_TRUNC, 0666);
\n if (fd < 0) {
\n perror("open");
\n return 0;
\n }
\n printf("hello world: %d\\\\n", fd);
\n fflush(stdout);
\n close(fd);
\n return 0;
\n}<\/p>\n
\u8fd8\u6709\u4e00\u79cd\u89e3\u51b3\u65b9\u6cd5，\u5e76\u4e14\u53ef\u4ee5\u9a8c\u8bc1stderr\u662f\u4e0d\u5e26\u7f13\u51b2\u533a\u7684<\/p>\n
#include <stdio.h>
\n#include <string.h>
\n#include <sys\/types.h>
\n#include <sys\/stat.h>
\n#include <fcntl.h>
\n#include <unistd.h><\/p>\n
int main() {
\n close(2);
\n int fd = open("log.txt", O_WRONLY | O_CREAT | O_TRUNC, 0666);
\n if (fd < 0) {
\n perror("open");
\n return 0;
\n }
\n perror("hello world");
\n close(fd);
\n return 0;
\n}<\/p>\n
\u8fd9\u79cd\u65b9\u5f0f\u53ef\u4ee5\u5c062\u53f7\u6587\u4ef6\u63cf\u8ff0\u7b26\u91cd\u5b9a\u5411\u81f3\u6587\u4ef6，\u7531\u4e8estderr\u6ca1\u6709\u7f13\u51b2\u533a，\u201chello world\u201d\u4e0d\u7528fflush\u5c31\u53ef\u4ee5\u5199\u5165\u6587\u4ef6：<\/p>\n
[sjx@VM-8-12-centos buffer]$ .\/myfile
\n[sjx@VM-8-12-centos buffer]$ cat log.txt
\nhello world: Success<\/p>\n
\u25cf\u56e0\u4e3aIO\u76f8\u5173\u51fd\u6570\u4e0e\u7cfb\u7edf\u8c03\u7528\u63a5\u53e3\u5bf9\u5e94，\u5e76\u4e14\u5e93\u51fd\u6570\u5c01\u88c5\u7cfb\u7edf\u8c03\u7528，\u6240\u4ee5\u672c\u8d28\u4e0a，\u8bbf\u95ee\u6587\u4ef6\u90fd\u662f\u901a\u8fc7fd\u8bbf\u95ee\u7684<\/p>\n
\u25cf\u6240\u4ee5C\u5e93\u4e2dFILE\u7ed3\u6784\u4f53\u5185\u90e8，\u5fc5\u5b9a\u5c01\u88c5\u4e86fd<\/p>\n
#include <stdio.h>
\n#include <string.h><\/p>\n
int main()
\n{
\n const char *msg0="hello printf\\\\n";
\n const char *msg1="hello fwrite\\\\n";
\n const char *msg2="hello write\\\\n";
\n printf("%s", msg0);
\n fwrite(msg1, strlen(msg0), 1, stdout);
\n write(1, msg2, strlen(msg2));
\n fork();
\n return 0;
\n}<\/p>\n
\u7ed3\u679c：<\/p>\n
hello printf<\/p>\n
hello fwrite<\/p>\n
hello write<\/p>\n
\u4f46\u82e5\u5bf9\u8fdb\u7a0b\u5b9e\u73b0\u8f93\u51fa\u91cd\u5b9a\u5411，.\/hello > file，\u7ed3\u679c\u5c31\u53d8\u6210\u4e86：<\/p>\n
hello write<\/p>\n
hello printf<\/p>\n
hello fwrite<\/p>\n
hello printf<\/p>\n
hello fwrite<\/p>\n
\u5176\u4e2dprintf\u548cfwrite（\u5e93\u51fd\u6570）\u90fd\u8f93\u51fa\u4e862\u6b21，\u800cwrite\u53ea\u8f93\u51fa\u4e86\u4e00\u6b21（\u7cfb\u7edf\u8c03\u7528）\u3002\u4e3a\u4ec0\u4e48fork\u4f1a\u5bfc\u81f4\u8fd9\u79cd\u7ed3\u679c？<\/p>\n
\u25cf\u4e00\u822cC\u5e93\u51fd\u6570\u5199\u5165\u6587\u4ef6\u65f6\u662f\u5168\u7f13\u51b2\u7684，\u800c\u5199\u5165\u663e\u793a\u5668\u662f\u884c\u7f13\u51b2<\/p>\n
\u25cfprintf\u3001fwrite\u5e93\u51fd\u6570\u4f1a\u81ea\u5e26\u7f13\u51b2\u533a，\u5f53\u53d1\u751f\u91cd\u5b9a\u5411\u5230\u666e\u901a\u6587\u4ef6\u65f6，\u6570\u636e\u7684\u7f13\u51b2\u65b9\u5f0f\u7531\u884c\u7f13\u51b2\u53d8\u6210\u4e86\u5168\u7f13\u51b2<\/p>\n
\u25cf\u800c\u6211\u4eec\u653e\u51fa\u7f13\u51b2\u533a\u4e2d\u7684\u6570\u636e，\u5c31\u4e0d\u4f1a\u88ab\u7acb\u5373\u5237\u65b0，\u8bbe\u7f6efork\u4e4b\u540e<\/p>\n
\u25cf\u4f46\u662f\u8fdb\u7a0b\u9000\u51fa\u540e，\u4f1a\u7edf\u4e00\u5c5e\u6027，\u5199\u5165\u6587\u4ef6\u5f53\u4e2d<\/p>\n
\u25cf\u4f46\u662ffork\u7684\u65f6\u5019，\u7236\u5b50\u6570\u636e\u4f1a\u53d1\u751f\u5199\u65f6\u62f7\u8d1d，\u5f53\u7236\u8fdb\u7a0b\u51c6\u5907\u5237\u65b0\u7684\u65f6\u5019，\u5b50\u8fdb\u7a0b\u4e5f\u5c31\u6709\u4e86\u76f8\u540c\u7684\u4e00\u4efd\u6570\u636e，\u6240\u4ee5\u4ea7\u751f\u4e24\u4efd\u6570\u636e<\/p>\n
\u25cf\u4f46write\u53ea\u8f93\u51fa\u4e00\u6b21，\u662f\u56e0\u4e3a，write\u662f\u7cfb\u7edf\u8c03\u7528，\u76f4\u63a5\u5199\u5230\u5185\u6838\u7f13\u51b2\u533a<\/p>\n
\u7efc\u4e0a：printf，fwrite\u5e93\u51fd\u6570\u4f1a\u81ea\u5e26\u7f13\u51b2\u533a，\u800cwrite\u7cfb\u7edf\u8c03\u7528\u6ca1\u6709\u5e26\u7f13\u51b2\u533a\u3002\u53e6\u5916，\u4e0a\u6587\u63d0\u5230\u7684\u7f13\u51b2\u533a，\u90fd\u662f\u7528\u6237\u7ea7\u7f13\u51b2\u533a\u3002\u5b9e\u9645\u4e0a\u4e3a\u4e86\u63d0\u5347\u6574\u673a\u6027\u80fd，OS\u4e5f\u4f1a\u63d0\u4f9b\u76f8\u5173\u5185\u6838\u7ea7\u7f13\u51b2\u533a\u3002<\/p>\n
\u90a3\u8fd9\u4e2a\u7f13\u51b2\u533a\u7531\u8c01\u63d0\u4f9b？printf，fwrite\u662f\u5e93\u51fd\u6570，write\u662f\u7cfb\u7edf\u8c03\u7528，\u5e93\u51fd\u6570\u5728\u7cfb\u7edf\u8c03\u7528\u7684\u201c\u4e0a\u5c42\u201d，\u662f\u5bf9\u7cfb\u7edf\u8c03\u7528\u7684\u201c\u5c01\u88c5\u201d，\u4f46\u662fwrite\u6ca1\u6709\u63d0\u4f9b\u7f13\u51b2\u533a（\u7528\u6237\u7ea7），\u800cprintf，fwrite\u6709，\u5c31\u53ef\u4ee5\u8bf4\u660e，\u8be5\u7f13\u51b2\u533a\u662f\u4e8c\u6b21\u52a0\u4e0a\u7684，\u56e0\u4e3a\u662fC\u5e93\u51fd\u6570，\u6240\u4ee5\u7531C\u6807\u51c6\u5e93\u63d0\u4f9b\u3002<\/p>\n
C\u5e93\u4e2dFILE\u7ed3\u6784\u4f53： \u00a0<\/p>\n
\u5728\/usr\/include\/libio.h
\nstruct _IO_FILE {
\n int _flags; \/* High-order word is _IO_MAGIC; rest is flags.
\n*\/
\n#define _IO_file_flags _flags
\n \/\/\u7f13\u51b2\u533a\u76f8\u5173
\n \/* The following pointers correspond to the C++ streambuf protocol. *\/
\n \/* Note: Tk uses the _IO_read_ptr and _IO_read_end fields directly. *\/
\n char* _IO_read_ptr; \/* Current read pointer *\/
\n char* _IO_read_end; \/* End of get area. *\/
\n char* _IO_read_base; \/* Start of putback+get area. *\/
\n char* _IO_write_base; \/* Start of put area. *\/
\n char* _IO_write_ptr; \/* Current put pointer. *\/
\n char* _IO_write_end; \/* End of put area. *\/
\n char* _IO_buf_base; \/* Start of reserve area. *\/
\n char* _IO_buf_end; \/* End of reserve area. *\/
\n \/* The following fields are used to support backing up and undo. *\/
\n char *_IO_save_base; \/* Pointer to start of non-current get area. *\/
\n char *_IO_backup_base; \/* Pointer to first valid character of backup area
\n *\/
\n char *_IO_save_end; \/* Pointer to end of non-current get area. *\/
\n struct _IO_marker *_markers;
\n struct _IO_FILE *_chain;
\n int _fileno; \/\/\u5c01\u88c5\u7684\u2f42\u4ef6\u63cf\u8ff0\u7b26
\n#if 0
\n int _blksize;
\n#else
\n int _flags2;
\n#endif
\n _IO_off_t _old_offset; \/* This used to be _offset but it's too small. *\/
\n#define __HAVE_COLUMN \/* temporary *\/
\n \/* 1+column number of pbase(); 0 is unknown. *\/
\n unsigned short _cur_column;
\n signed char _vtable_offset;
\n char _shortbuf[1];
\n \/* char* _save_gptr; char* _save_egptr; *\/
\n _IO_lock_t *_lock;
\n#ifdef _IO_USE_OLD_IO_FILE
\n};<\/p>\n
mystdio.h<\/p>\n
#pragma once<\/p>\n
#include <stdio.h><\/p>\n
#define MAX 1024
\n\/\/\u7f13\u51b2\u533a\u5237\u65b0
\n#define NONE_FLUSH 1
\n#define LINE_FLUSH 2
\n#define FULL_FLUSH 3<\/p>\n
typedef struct IO_FILE{
\n int fileno;
\n int filemode;
\n char outbuffer[MAX];
\n int bufferlen;
\n int flush_method;
\n}MyFile;<\/p>\n
MyFile* MyFOpen(const char *path, const char *mode);
\nvoid MyFClose(MyFile *);
\nint MyFWrite(MyFile *,void *str,int len);
\nvoid MyFFlush(MyFile* );<\/p>\n
mystdio.c<\/p>\n
#include "mystdio.h"<\/p>\n
#include <string.h>
\n#include <sys\/types.h>
\n#include <sys\/stat.h>
\n#include <fcntl.h>
\n#include <stdlib.h>
\n#include <unistd.h><\/p>\n
static MyFile* buyfile(int fd,int filemode){
\n MyFile* file=(MyFile*)malloc(sizeof(MyFile));
\n if(file==NULL) return NULL;
\n file->filemode=filemode;
\n file->fileno=fd;
\n file->bufferlen=0;
\n file->flush_method=LINE_FLUSH;
\n memset(file->outbuffer,0,sizeof(file->outbuffer));
\n return file;
\n}<\/p>\n
MyFile* MyFOpen(const char *path, const char *mode){
\n int fd=-1;
\n int filemode=0;
\n if(strcmp(mode,"w")==0){
\n filemode=O_CREAT|O_WRONLY|O_TRUNC;
\n }
\n else if(strcmp(mode,"r")==0){
\n filemode=O_RDONLY;
\n }
\n else if(strcmp(mode,"a")==0){
\n filemode=O_CREAT|O_WRONLY|O_APPEND;
\n }
\n else{
\n \/\/
\n }
\n fd=open(path,filemode,0666);<\/p>\n
if(fd<0) return NULL;
\n return buyfile(fd,filemode);
\n}<\/p>\n
void MyFClose(MyFile *file){
\n if(file->filemode<0) return ;
\n MyFFlush(file);
\n file->fileno=0;
\n free(file);
\n}<\/p>\n
int MyFWrite(MyFile *file,void *str,int len){
\n \/\/1.\u62f7\u8d1d
\n memcpy(file->outbuffer+file->bufferlen,str,len);
\n file->bufferlen+=len;
\n \/\/\u5224\u65ad\u5237\u65b0
\n if((file->flush_method&LINE_FLUSH)&&(file->outbuffer[file->bufferlen-1]=='\\\\n'))
\n MyFFlush(file);
\n return 0;
\n}<\/p>\n
void MyFFlush(MyFile* file){
\n \/\/\u628a\u6570\u636e\u4ece\u7528\u6237\u62f7\u8d1d\u5230\u5185\u6838\u6587\u4ef6\u7f13\u51b2\u533a\u4e2d
\n int n=write(file->fileno,file->outbuffer,file->bufferlen);
\n (void)n;\/\/\u6d88\u9664\u7f16\u8bd1\u5668\u62a5\u8b66
\n fsync(file->fileno);\/\/\u5f3a\u5236\u5c06\u6587\u4ef6\u6570\u636e\u548c\u5143\u6570\u636e\u4ece\u5185\u6838\u9875\u7f13\u5b58\u5199\u5165\u78c1\u76d8
\n file->bufferlen=0;
\n}<\/p>\n
usercode.c<\/p>\n
#include "mystdio.h"
\n#include <string.h>
\n#include <unistd.h><\/p>\n
int main(){
\n MyFile* fp=MyFOpen("log.txt","w");
\n if(!fp){
\n printf("MyfOpen failed\\\\n");
\n return 1;
\n }
\n const char* msg="hello world";
\n int cnt=10;
\n while(cnt–){
\n MyFWrite(fp,(char*)msg,strlen(msg));
\n MyFFlush(fp);
\n printf("buffer:%s\\\\n",fp->outbuffer);
\n sleep(1);
\n }
\n MyFClose(fp);
\n return 0;
\n}<\/p>\n<\/p><\/p>\n","protected":false},"excerpt":{"rendered":"
💁\u200d\u2642\ufe0f\u4e2a\u4eba\u4e3b\u9875：\u8fdb\u51fb\u7684\u8346\u68d8 👇\u4f5c\u8005\u5176\u5b83\u4e13\u680f： \u300a\u6570\u636e\u7ed3\u6784\u4e0e\u7b97\u6cd5\u300b\u300a\u7b97\u6cd5\u300b\u300aC\u8d77\u59cb\u4e4b\u8def\u300b\u300aLinux\u300b \u76ee\u5f55
\n1.\u7406\u89e3\u201c\u6587\u4ef6\u201d
\n2.C\u6587\u4ef6\u63a5\u53e3
\n3.\u7cfb\u7edf\u6587\u4ef6I\/O
\n4.\u7406\u89e3\u201c\u4e00\u5207\u7686\u6587\u4ef6\u201d
\n5.\u7f13\u51b2\u533a 4.\u7406\u89e3\u201c\u4e00\u5207\u7686\u6587\u4ef6\u201d
\n\u9996\u5148，\u5728windows\u4e2d\u662f\u6587\u4ef6\u7684\u4e1c\u897f，\u5728linux\u4e2d\u4e5f\u662f\u6587\u4ef6；\u5176\u6b21\u4e00\u4e9b\u5728windows\u4e2d\u4e0d\u662f\u6587\u4ef6\u7684\u4e1c\u897f，\u5982：\u8fdb\u7a0b\u3001<\/p>\n","protected":false},"author":2,"featured_media":111525,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"topic":[],"class_list":["post-111526","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-server"],"yoast_head":"\n