Supported Standard IO System Call¶
Functions¶
-
int open(const char *path, int flags, ...)¶
open and possibly create a file
read more: man 2 open
- Parameters
path – file path
flags – flags
... –
- Returns
return file descriptor on success, -1 on failure
-
int close(int fd)¶
Close a file descriptor.
read more: man 2 close
- Parameters
fd – file descritor
- Returns
return file descriptor on success, -1 on failure
-
ssize_t read(int fd, void *buf, size_t count)¶
read from a file descriptor
- Parameters
fd – file descriptor
buf – buffer to store read data
count – number of bytes to read
- Returns
zero or number of bytes read on success, -1 on failure
-
ssize_t write(int fd, const void *buf, size_t count)¶
write to file descriptor
- Parameters
fd – file description
buf – buffer to write
count – number of bytes to write
- Returns
On success, the number of bytes written is returned. On error, -1 is returned
-
int fsync(int fd)¶
synchronize a file’s in-core state with storage device
- Parameters
fd – file descriptor
- Returns
On success, these system calls return zero. On error, -1 is returned
-
int isatty(int fd)¶
test whether a file descriptor refers to a terminal
- Parameters
fd – file descriptor
- Returns
returns 1 if fd is an open file descriptor referring to a terminal; otherwise 0 is returned
-
off_t lseek(int fd, off_t offset, int whence)¶
reposition read/write file offset
- Parameters
fd – file descriptor
offset – offset value
whence – SEEK_SET, SEEK_CUR, SEEK_END
- Returns
resulting offset location on success, -1 on error
-
int ftruncate(int fd, off_t length)¶
truncate a file to a specified length
- Parameters
fd – file descriptor
length – new length
- Returns
On success, zero is returned. On error, -1 is returned
-
int fstat(int fd, struct stat *statbuf)¶
get file status
- Parameters
fd – file descriptor
statbuf – pointer to stat structure
- Returns
On success, zero is returned. On error, -1 is returned
-
int unlink(const char *pathname)¶
delete a file
- Parameters
pathname – path to file
- Returns
On success, zero is returned. On error, -1 is returned
-
int rename(const char *oldpath, const char *newpath)¶
change the name
- Parameters
oldpath – path to old file
newpath – path to new file
- Returns
On success, zero is returned. On error, -1 is returned
-
int access(const char *pathname, int mode)¶
check user’s permissions for a file
- Parameters
pathname – path to file
mode – the accessibility check(s) to be performed
- Returns
On success, zero is returned. On error, -1 is returned
-
int mkdir(const char *pathname, mode_t mode)¶
create a directory
- Parameters
pathname – path to directory
mode – mode for the new directory
- Returns
zero on success, or -1 if an error occurred
-
int rmdir(const char *pathname)¶
delete a directory
- Parameters
pathname – path to directory
- Returns
On success, zero is returned. On error, -1 is returned
-
int fcntl(int fd, int cmd, ...)¶
manipulate file descriptor
more details check: man 2 fcntl
Supported commmands: F_GETFL, F_SETFL, F_GETLK, F_SETLK, F_SETLKW
- Parameters
fd – file descriptor
cmd – operation to performed
... – argument
- Returns
On success, zero is returned. On error, -1 is returned
-
int lockf(int fd, int cmd, off_t len)¶
apply, test or remove a POSIX lock on an open file
- Parameters
fd – File descriptor
cmd – operation to perform
len – unimplemented, only complete file locking possible
- Returns
On success, zero is returned. On error, -1 is returned
-
int flock(int fd, int operation)¶
apply or remove an advisory lock on an open file
- Parameters
fd – File descriptor
operation – operation to perform: LOCK_SH, LOCK_EX, LOCK_UN
- Returns
On success, zero is returned. On error, -1 is returned
-
pid_t getpid(void)¶
returns current task id
- Returns
returns taskid of current task