gtpc2m24 | C/C++ Language Support User's Guide |
This function changes the owner and group by a file descriptor.
Format
#include <unistd.h> int fchown(int fildes, uid_t owner, gid_t group);
A process can change the group of a file only if the effective user ID of the process is equal to the user ID of the file owner or if the process has appropriate privileges (superuser authority). If the file is a regular file and the process does not have superuser authority, the chown function clears the S_ISUID and S_ISGID bits in the mode of the file.
TPF deviation from POSIX |
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The TPF system does not support the ctime time stamp. |
Normal Return
If successful, the fchown function updates the owner and group for the file and returns 0.
Error Return
If unsuccessful, the fchown function returns -1 and sets errno to one of the following:
Programming Considerations
None.
Examples
The following example changes the owner ID and group ID.
#include <fcntl.h> #include <unistd.h> #include <sys/stat.h> #include <sys/types.h> #include <stdio.h> main() { char fn[]="temp.file"; int fd; struct stat info; if ((fd = creat(fn, S_IWUSR)) < 0) perror("creat() error"); else { stat(fn, &info); printf("original owner was %d and group was %d\n", info.st_uid, info.st_gid); if (fchown(fd, 25, 0) != 0) perror("fchown() error"); else { stat(fn, &info); printf("after fchown(), owner is %d and group is %d\n", info.st_uid, info.st_gid); } close(fd); unlink(fn); } }
Output
original owner was 256 and group was 257 after fchown(), owner is 25 and group is 0
Related Information
See Appendix E, Programming Support for the TPF File System for more information about TPF File System C Functions.