![open I/O
int open(char* path, int access, ...);
open unsigned
mode mode access path
access mode FCNTL.h access
#define O_RDONLY 1
#define O_WRONLY 2
#define O_RDWR 4
access flag
#define O_CREAT 0x0100 /* create and open file */
#define O_TRUNC 0x0200 /* open with truncation */
#define O_EXCL 0x0400 /* exclusive open */
#define O_APPEND 0x0800 /* to end of file */
#define O_CHANGED 0x1000 /* user may read these
bits, but */
#define O_DEVICE 0x2000 /* only RTLio functions
may touch. */
#define O_TEXT 0x4000 /* CR-LF translation */
#define O_BINARY 0x8000 /* no translation */
O_CREAT mode mode sysstat.h
#define S_IREAD 0x0100 /* owner may read */
#define S_IWRITE 0x0080 /* owner may write */
open(s[i], 0x0100,0x0080); O_CREAT
s[i]](https://image.slidesharecdn.com/unixopen-110405212443-phpapp02/85/Unix-open-1-320.jpg)
Unix open
- 1. open I/O int open(char* path, int access, ...); open unsigned mode mode access path access mode FCNTL.h access #define O_RDONLY 1 #define O_WRONLY 2 #define O_RDWR 4 access flag #define O_CREAT 0x0100 /* create and open file */ #define O_TRUNC 0x0200 /* open with truncation */ #define O_EXCL 0x0400 /* exclusive open */ #define O_APPEND 0x0800 /* to end of file */ #define O_CHANGED 0x1000 /* user may read these bits, but */ #define O_DEVICE 0x2000 /* only RTLio functions may touch. */ #define O_TEXT 0x4000 /* CR-LF translation */ #define O_BINARY 0x8000 /* no translation */ O_CREAT mode mode sysstat.h #define S_IREAD 0x0100 /* owner may read */ #define S_IWRITE 0x0080 /* owner may write */ open(s[i], 0x0100,0x0080); O_CREAT s[i]
- 2. int open(const char *path, int access,int mode) -1 path access O_RDONLY 1 ; O_WRONLY 2 ; O_RDWR 4 3 O_CREAT 0x0100 O_TRUNC 0x0200 0, O_EXCL 0x0400 O_APPEND 0x0800 O_TEXT 0x4000 CR-LF O_BINARY 0x8000 CR-LF mode access=O_CREAT S_IFMT 0xF000 S_IFDIR 0x4000 S_IFIFO 0x1000 FIFO S_IFCHR 0x2000 S_IFBLK 0x3000 S_IFREG 0x8000 0x0000 S_IREAD 0x0100
- 3. S_IWRITE 0x0080 S_IEXEC 0x0040 int open(const char *path, int access,int mode) ------------------------------------------------ mode access O_CREAT open access mode tc2.0 tc3.1 vc6.0 C++Builder gcc open gcc: _CRTIMP int __cdecl _open (const char*, int, ...); VC6.0 _CRTIMP int __cdecl _open(const char *, int, ...); Borland C++Builder int _RTLENTRY _EXPFUNC open(const char _FAR *__path, int __access,... /*unsigned mode*/); tc3.1 int _Cdecl _FARFUNC open(const char _FAR *__path, int __access,... /*unsigned mode*/); tc2.0 int _Cdecl open (const char *path, int access,... /*unsigned mode*/);