- 与文件存储有关的系统调用
- write
- read
- open
- close
- ioctl
- lseek
- fstat，stat，lstat
- dup，dup2
#include#include #include #include #include #include #include #include using namespace std; int main(){ int fp; mode_t fp_mode; fp_mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH; fp = open("test.txt", O_RDWR | O_CREAT, fp_mode); if ( fp != -1 ){ printf("file created successfully!\n"); }else{ printf("failed!"); } struct stat *buf = (struct stat*)malloc(sizeof(struct stat)); if ( buf != NULL ){ printf("buffer created successfully!\n"); }else{ printf("buffer created failed!\n"); } fstat(fp, buf); if(buf->st_mode & S_IRUSR){ printf("owner has read access!\n"); } if(buf->st_mode & S_IWGRP){ printf("group has write access!\n"); }else{ puts("group has no write access!"); } close(fp); chmod("test.txt", 0664); stat("test.txt", buf); if(buf->st_mode & S_IWGRP){ puts("group has write access!"); } free(buf); char *dir = (char*)malloc(50); if(dir != NULL){ getcwd(dir, 50); printf("current dir:%s\n", dir); } if(mkdir("test", 775) != -1){ puts("dir created successfully!"); chdir("test"); puts("change workspace to test"); }else{ puts("couldn't create test dir!"); } free(dir); return 0; } #include#include #include #include #include #include #define LENGTH 2000 void copy(char* oldfile, char* newfile); int main(int argc, char* argv[]) { if(argc != 3){ puts("invalid arguments!\n"); return 1; } copy(argv[1], argv[2]); return 0; } void copy(char* oldfile, char* newfile) { char buf[LENGTH]; int f1,f2,i, j=0; mode_t f_mode = S_IRUSR | S_IWUSR | S_IRGRP; f1 = open(oldfile, O_RDONLY); if(f1!= -1){ puts("file opened successfully!\n"); i = read(f1, buf, LENGTH); if(i>0){ printf("%s\n",buf); } f2 = open(newfile, O_WRONLY|O_CREAT, f_mode); if(f2 != -1){ write(f2, buf, i); }else{ puts("create file failed!\n"); } puts("write completed!\n"); close(f2); }else{ puts("read file failed!"); perror("file:"); } close(f1); }
- 文件存取库函数
- fopen，fclose
- fread，fwrite
- fflush
- fseek
- fgetc，getc，getchar
- fputc， putc，putchar
- fgets，gets
#include#define SIZE 65535 #define LENGTH 1024 int main(){ FILE *fp,*fp_copy; char buf[SIZE]; fp = fopen("test.cpp","r"); if(fp != NULL){ puts("文件打开成功！"); if(fread(buf, LENGTH, SIZE/LENGTH, fp) > 0){ puts("文件读取成功！"); }else{ puts("文件读取失败!"); } }else{ perror("open file:"); return 1; } fp_copy = fopen("test.txt", "w"); if(fp_copy != NULL){ puts("正在写入文件！"); if(fwrite(buf, LENGTH, SIZE/LENGTH, fp_copy) >0){ puts("文件写入成功！"); }else{ puts("写入失败！"); } } if(fclose(fp)!= -1 && fclose(fp_copy) != -1){ puts("文件关闭成功！"); }else{ perror("close file:"); return 1; } return 0; }
- format input and output
- printf, sprintf, fprintf
- scanf, sscanf, fscanf
#include#include typedef struct{ char name[20]; char address[50]; char stu_id[15]; } student; int main(){ student stu1; FILE *fp; if(creat("info.txt",0664) == -1){ perror("创建文件失败！"); return 1; } fp = fopen("info.txt","w"); if(fp != NULL){ fprintf(fp," :%s :%s :%s","xiaoming", "Beijing", "1010101"); puts("输出信息成功!"); } fclose(fp); fp = fopen("info.txt","r"); fscanf(fp," :%s :%s :%s", stu1.name, stu1.address, stu1.stu_id); fclose(fp); printf("%s,%s,%s\n",stu1.name,stu1.address,stu1.stu_id); return 0; }
- file des position
- fgetpos, fsetpos
- ftell
- rewind
- freopen
- setvbuf
- remove
#include#include #include #include #define CTIME 3 typedef struct{ int length; fpos_t fpos; } pos_t; int main(){ pos_t pos[CTIME]; FILE *fp; if(creat("temp",0664) == -1){ perror("创建文件失败！"); return 1; } fp = fopen("temp","rw+"); for(int i = 0; i< CTIME; i++){ fgetpos(fp, &pos[i].fpos); pos[i].length = fprintf(fp, "第%d次输出的数据！\n", i); } fflush(fp); printf("文件总长度:%d\n", ftell(fp)); rewind(fp); char *buf; for(int i =0; i < CTIME ; i++){ fsetpos(fp, &pos[i].fpos); buf = (char*)malloc(pos[i].length + 1); *(buf + pos[i].length +1) = '\0'; fread(buf, pos[i].length, 1, fp); printf("%s",buf); free(buf); } fclose(fp); return 0; }
- error detect
- ferror
- feof
- clearerr
- Streams and file descriptors
- fileno
get fd from Stream - fdopen
open a stream from fd
- fileno
- file and directory maintence
-
chmod
-
chown
-
link
- rmdir, mkdir
- chdir, getcwd
-
- scan dir
- opendir, closedir
- readdir, telldir, seekdir
#include#include #include #include #include #include #include #include void scan_dir(char *dir, int depth); int main(){ puts("scan dir /boot\n"); scan_dir("/boot",0); puts("scan completed!\n"); return 0; } void scan_dir(char *dir, int depth){ DIR *dp; struct dirent *entry; struct stat statbuf; if(dir==NULL){ puts("you must input a dirname!"); return; } if((dp = opendir(dir)) == NULL){ printf("couldn't open the folder:%s\n", dir); return; }else{ chdir(dir); while((entry = readdir(dp)) != NULL){ lstat(entry->d_name, &statbuf); if(S_IFDIR & statbuf.st_mode){ if(strcmp(entry->d_name,".")==0 || strcmp(entry->d_name,"..")==0){ continue; } printf("%*s%s/\n",depth, " ",entry->d_name); scan_dir(entry->d_name,depth+4); }else{ printf("%*s%s\n", depth," ", entry->d_name); } } chdir(".."); closedir(dp); } }
- error process
- strerror,perror
