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