Open System Services System Calls Reference Manual (G06.27+, H06.04+)

System Functions (k - m) mknod(2)
S_ISGID Set the group ID of the file upon execution of the file
S_ISUID Set the user ID of the file upon execution of the file
S_ISVTX Restrict the deletion of files in a directory (ignored for other file
types)
S_IWGRP Write access by members of the group list
S_IWOTH Write access by others
S_IWUSR Write access by the owner of the file
S_IXGRP Execute (search) access by members of the group list
S_IXOTH Execute (search) access by others
S_IXUSR Execute (search) access by the owner of the file
device Specifies the type of device on which the file is created. This hexadecimal value
must be 0 (zero) unless the file type S_IFCHR is specified for the mode parame-
ter. When S_IFCHR is specified, the following values are valid:
0x0000000300000000
The device is an infinite data source or data sink, such as
/dev/null.
0x0000000200000000
The device is a controlling terminal, such as /dev/tty.
Specifying any other value for the device parameter when S_IFCHR is specified
for the mode parameter causes the function call to fail and errno to be set to
[EINVAL].
DESCRIPTION
The mknod() function creates a new special or regular file. Using the mknod( ) function to
create file types other than FIFOs requires appropriate privileges.
For the mknod() function to finish successfully, a process must have search permission and write
permission in the parent directory of the path parameter.
The new file has the following characteristics:
• A file type as specified by the mode parameter.
• An owner ID set to the effective user ID of the process.
• A group ID set to the effective group ID of the process or to the group ID of the parent
directory of the file.
• Access permission and attribute bits set according to the value of the mode parameter, as
modified by the settings of the file mode creation mask for the process. Access permis-
sion and attribute bits are cleared when the corresponding file mode creation mask bits
are set. (See the umask(2) reference page.)
Upon successful completion of the function call, the st_atime, st_ctime, and st_mtime fields of
the file are marked for update. The st_ctime and st_mtime fields of the directory that contains
the new entry are also marked for update.
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