What is a good way to test whether a file has required permissions?
I see that ifstream::open() returns void and does not offer any way to see if the file did not open due to permissions. What is a good api to test whether read permission or alternatively write permissions are available on a file for the current process in C++?
c++ file permissions
asked Dec 11 '09 at 2:23
WilliamKFWilliamKF
15k49145241
add a comment |
I see that ifstream::open() returns void and does not offer any way to see if the file did not open due to permissions. What is a good api to test whether read permission or alternatively write permissions are available on a file for the current process in C++?
c++ file permissions
asked Dec 11 '09 at 2:23
WilliamKFWilliamKF
15k49145241
1
I/O is OS specific, maybe if you could tell us your OS it would be possible to give a more specific answer.
– Anders
Dec 11 '09 at 2:30
Possible duplicate: stackoverflow.com/questions/1138508/…
– Dan Hook
Dec 11 '09 at 17:58
This is for Linux.
– WilliamKF
Dec 12 '09 at 0:30
add a comment |
I see that ifstream::open() returns void and does not offer any way to see if the file did not open due to permissions. What is a good api to test whether read permission or alternatively write permissions are available on a file for the current process in C++?
c++ file permissions
asked Dec 11 '09 at 2:23
WilliamKFWilliamKF
15k49145241
I see that ifstream::open() returns void and does not offer any way to see if the file did not open due to permissions. What is a good api to test whether read permission or alternatively write permissions are available on a file for the current process in C++?
c++ file permissions
c++ file permissions
asked Dec 11 '09 at 2:23
WilliamKFWilliamKF
15k49145241
asked Dec 11 '09 at 2:23
WilliamKFWilliamKF
15k49145241
asked Dec 11 '09 at 2:23
WilliamKFWilliamKF
15k49145241
asked Dec 11 '09 at 2:23
WilliamKFWilliamKF
15k49145241
asked Dec 11 '09 at 2:23
WilliamKFWilliamKF
15k49145241
15k49145241
1
I/O is OS specific, maybe if you could tell us your OS it would be possible to give a more specific answer.
– Anders
Dec 11 '09 at 2:30
Possible duplicate: stackoverflow.com/questions/1138508/…
– Dan Hook
Dec 11 '09 at 17:58
This is for Linux.
– WilliamKF
Dec 12 '09 at 0:30
add a comment |
1
I/O is OS specific, maybe if you could tell us your OS it would be possible to give a more specific answer.
– Anders
Dec 11 '09 at 2:30
Possible duplicate: stackoverflow.com/questions/1138508/…
– Dan Hook
Dec 11 '09 at 17:58
This is for Linux.
– WilliamKF
Dec 12 '09 at 0:30
1
1
I/O is OS specific, maybe if you could tell us your OS it would be possible to give a more specific answer.
– Anders
Dec 11 '09 at 2:30
I/O is OS specific, maybe if you could tell us your OS it would be possible to give a more specific answer.
– Anders
Dec 11 '09 at 2:30
Possible duplicate: stackoverflow.com/questions/1138508/…
– Dan Hook
Dec 11 '09 at 17:58
Possible duplicate: stackoverflow.com/questions/1138508/…
– Dan Hook
Dec 11 '09 at 17:58
This is for Linux.
– WilliamKF
Dec 12 '09 at 0:30
This is for Linux.
– WilliamKF
Dec 12 '09 at 0:30
add a comment |
4 Answers
4
active
oldest
votes
Try the POSIX access() function, in unistd.h
answered Dec 11 '09 at 2:29
Paul BeckinghamPaul Beckingham
11.4k32663
add a comment |
You can also use stat which returns a bunch of information, including mode, uid and gid:
struct stat {
dev_t st_dev; /* ID of device containing file */
ino_t st_ino; /* inode number */
mode_t st_mode; /* protection */
nlink_t st_nlink; /* number of hard links */
uid_t st_uid; /* user ID of owner */
gid_t st_gid; /* group ID of owner */
dev_t st_rdev; /* device ID (if special file) */
off_t st_size; /* total size, in bytes */
blksize_t st_blksize; /* blocksize for file system I/O */
blkcnt_t st_blocks; /* number of 512B blocks allocated */
time_t st_atime; /* time of last access */
time_t st_mtime; /* time of last modification */
time_t st_ctime; /* time of last status change */
};
I am not aware of nice C++ wrappers for these lower-level functions.
answered Dec 11 '09 at 2:32
Dirk EddelbuettelDirk Eddelbuettel
279k38515603
add a comment |
If your using windows , you can use GetFileAttributesEx to check the attributes of the file. If its read-only, you might need to call SetFileAttributes to unset the read-only flag.
answered Dec 11 '09 at 2:36
Andrew KeithAndrew Keith
6,64411938
add a comment |
You can use the chmod command.
It has 3 digits, corresponding to owner,group,other user
777 stands for max permissions.
answered Nov 20 '18 at 11:22
Akash VermaAkash Verma
2029
add a comment |
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4 Answers
4
active
oldest
votes
4 Answers
4
active
oldest
votes
active
oldest
votes
active
oldest
votes
Try the POSIX access() function, in unistd.h
answered Dec 11 '09 at 2:29
Paul BeckinghamPaul Beckingham
11.4k32663
add a comment |
Try the POSIX access() function, in unistd.h
answered Dec 11 '09 at 2:29
Paul BeckinghamPaul Beckingham
11.4k32663
add a comment |
Try the POSIX access() function, in unistd.h
answered Dec 11 '09 at 2:29
Paul BeckinghamPaul Beckingham
11.4k32663
Try the POSIX access() function, in unistd.h
answered Dec 11 '09 at 2:29
Paul BeckinghamPaul Beckingham
11.4k32663
answered Dec 11 '09 at 2:29
Paul BeckinghamPaul Beckingham
11.4k32663
answered Dec 11 '09 at 2:29
Paul BeckinghamPaul Beckingham
11.4k32663
answered Dec 11 '09 at 2:29
Paul BeckinghamPaul Beckingham
11.4k32663
11.4k32663
add a comment |
add a comment |
You can also use stat which returns a bunch of information, including mode, uid and gid:
struct stat {
dev_t st_dev; /* ID of device containing file */
ino_t st_ino; /* inode number */
mode_t st_mode; /* protection */
nlink_t st_nlink; /* number of hard links */
uid_t st_uid; /* user ID of owner */
gid_t st_gid; /* group ID of owner */
dev_t st_rdev; /* device ID (if special file) */
off_t st_size; /* total size, in bytes */
blksize_t st_blksize; /* blocksize for file system I/O */
blkcnt_t st_blocks; /* number of 512B blocks allocated */
time_t st_atime; /* time of last access */
time_t st_mtime; /* time of last modification */
time_t st_ctime; /* time of last status change */
};
I am not aware of nice C++ wrappers for these lower-level functions.
answered Dec 11 '09 at 2:32
Dirk EddelbuettelDirk Eddelbuettel
279k38515603
add a comment |
You can also use stat which returns a bunch of information, including mode, uid and gid:
struct stat {
dev_t st_dev; /* ID of device containing file */
ino_t st_ino; /* inode number */
mode_t st_mode; /* protection */
nlink_t st_nlink; /* number of hard links */
uid_t st_uid; /* user ID of owner */
gid_t st_gid; /* group ID of owner */
dev_t st_rdev; /* device ID (if special file) */
off_t st_size; /* total size, in bytes */
blksize_t st_blksize; /* blocksize for file system I/O */
blkcnt_t st_blocks; /* number of 512B blocks allocated */
time_t st_atime; /* time of last access */
time_t st_mtime; /* time of last modification */
time_t st_ctime; /* time of last status change */
};
I am not aware of nice C++ wrappers for these lower-level functions.
answered Dec 11 '09 at 2:32
Dirk EddelbuettelDirk Eddelbuettel
279k38515603
add a comment |
You can also use stat which returns a bunch of information, including mode, uid and gid:
struct stat {
dev_t st_dev; /* ID of device containing file */
ino_t st_ino; /* inode number */
mode_t st_mode; /* protection */
nlink_t st_nlink; /* number of hard links */
uid_t st_uid; /* user ID of owner */
gid_t st_gid; /* group ID of owner */
dev_t st_rdev; /* device ID (if special file) */
off_t st_size; /* total size, in bytes */
blksize_t st_blksize; /* blocksize for file system I/O */
blkcnt_t st_blocks; /* number of 512B blocks allocated */
time_t st_atime; /* time of last access */
time_t st_mtime; /* time of last modification */
time_t st_ctime; /* time of last status change */
};
I am not aware of nice C++ wrappers for these lower-level functions.
answered Dec 11 '09 at 2:32
Dirk EddelbuettelDirk Eddelbuettel
279k38515603
You can also use stat which returns a bunch of information, including mode, uid and gid:
struct stat {
dev_t st_dev; /* ID of device containing file */
ino_t st_ino; /* inode number */
mode_t st_mode; /* protection */
nlink_t st_nlink; /* number of hard links */
uid_t st_uid; /* user ID of owner */
gid_t st_gid; /* group ID of owner */
dev_t st_rdev; /* device ID (if special file) */
off_t st_size; /* total size, in bytes */
blksize_t st_blksize; /* blocksize for file system I/O */
blkcnt_t st_blocks; /* number of 512B blocks allocated */
time_t st_atime; /* time of last access */
time_t st_mtime; /* time of last modification */
time_t st_ctime; /* time of last status change */
};
I am not aware of nice C++ wrappers for these lower-level functions.
answered Dec 11 '09 at 2:32
Dirk EddelbuettelDirk Eddelbuettel
279k38515603
answered Dec 11 '09 at 2:32
Dirk EddelbuettelDirk Eddelbuettel
279k38515603
answered Dec 11 '09 at 2:32
Dirk EddelbuettelDirk Eddelbuettel
279k38515603
answered Dec 11 '09 at 2:32
Dirk EddelbuettelDirk Eddelbuettel
279k38515603
279k38515603
add a comment |
add a comment |
If your using windows , you can use GetFileAttributesEx to check the attributes of the file. If its read-only, you might need to call SetFileAttributes to unset the read-only flag.
answered Dec 11 '09 at 2:36
Andrew KeithAndrew Keith
6,64411938
add a comment |
If your using windows , you can use GetFileAttributesEx to check the attributes of the file. If its read-only, you might need to call SetFileAttributes to unset the read-only flag.
answered Dec 11 '09 at 2:36
Andrew KeithAndrew Keith
6,64411938
add a comment |
If your using windows , you can use GetFileAttributesEx to check the attributes of the file. If its read-only, you might need to call SetFileAttributes to unset the read-only flag.
answered Dec 11 '09 at 2:36
Andrew KeithAndrew Keith
6,64411938
If your using windows , you can use GetFileAttributesEx to check the attributes of the file. If its read-only, you might need to call SetFileAttributes to unset the read-only flag.
answered Dec 11 '09 at 2:36
Andrew KeithAndrew Keith
6,64411938
answered Dec 11 '09 at 2:36
Andrew KeithAndrew Keith
6,64411938
answered Dec 11 '09 at 2:36
Andrew KeithAndrew Keith
6,64411938
answered Dec 11 '09 at 2:36
Andrew KeithAndrew Keith
6,64411938
6,64411938
add a comment |
add a comment |
You can use the chmod command.
It has 3 digits, corresponding to owner,group,other user
777 stands for max permissions.
answered Nov 20 '18 at 11:22
Akash VermaAkash Verma
2029
add a comment |
You can use the chmod command.
It has 3 digits, corresponding to owner,group,other user
777 stands for max permissions.
answered Nov 20 '18 at 11:22
Akash VermaAkash Verma
2029
add a comment |
You can use the chmod command.
It has 3 digits, corresponding to owner,group,other user
777 stands for max permissions.
answered Nov 20 '18 at 11:22
Akash VermaAkash Verma
2029
You can use the chmod command.
It has 3 digits, corresponding to owner,group,other user
777 stands for max permissions.
answered Nov 20 '18 at 11:22
Akash VermaAkash Verma
2029
answered Nov 20 '18 at 11:22
Akash VermaAkash Verma
2029
answered Nov 20 '18 at 11:22
Akash VermaAkash Verma
2029
answered Nov 20 '18 at 11:22
Akash VermaAkash Verma
2029
2029
add a comment |
add a comment |
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1
I/O is OS specific, maybe if you could tell us your OS it would be possible to give a more specific answer.
– Anders
Dec 11 '09 at 2:30
Possible duplicate: stackoverflow.com/questions/1138508/…
– Dan Hook
Dec 11 '09 at 17:58
This is for Linux.
– WilliamKF
Dec 12 '09 at 0:30