Visit Our UNIX and Linux User Community

Linux and UNIX Man Pages

Test Your Knowledge in Computers #516
Difficulty: Easy
Programming languages only support a single data type in order to insure faster execution.
True or False?
Linux & Unix Commands - Search Man Pages

getmntopts(3) [bsd man page]

GETMNTOPTS(3)						     Library Functions Manual						     GETMNTOPTS(3)

NAME
getmntopts - scan mount options SYNOPSIS
#include <mntopts.h> void getmntopts(options, mopts, flagp) char *options; struct mntopt *mopts; int *flagp DESCRIPTION
The getmntopts() function takes a comma separated option list and a list of valid option names, and computes the bitmask corresponding to the requested set of options. The string options is broken down into a sequence of comma separated tokens. Each token is looked up in the table described by mopts and the bits in the word referenced by flagp are updated. The flag word is not initialized by getmntopt. The table, mopts, has the following format: struct mntopt { char *m_option; /* option name */ int m_inverse; /* is this a negative option, eg "dev" */ int m_flag; /* bit to set, eg MNT_RDONLY */ }; The members of this structure are: m_option the option name, for example ``suid''. m_inverse tells getmntopts that the name has the inverse meaning of the bit. For example, ``suid'' is the string, whereas the mount flag is MNT_NOSUID. In this case, the sense of the string and the flag are inverted, so the m_inverse flag should be set. m_flag the value of the bit to be set or cleared in the flag word when the option is recognized. The bit is set when the option is dis- covered, but cleared if the option name was preceded by the letters ``no''. The m_inverse flag causes these two operations to be reversed. Each of the user visible MNT_ flags has a corresponding MOPT_ macro which defines an appropriate struct mntopt entry. To simplify the pro- gram interface and ensure consistency across all programs, a general purpose macro, MOPT_STDOPTS, is defined which contains an entry for all the generic VFS options. In addition, the macros MOPT_FORCE and MOPT_UPDATE exist to enable the MNT_FORCE and MNT_UPDATE flags to be set. Finally, the table must be terminated by an entry with a NULL first element. EXAMPLES
Most commands will use the standard option set. Local filesystems which support the MNT_UPDATE flag, would also have an MOPT_UPDATE entry. This can be declared and used as follows: #include "mntopts.h" struct mntopt mopts[] = { MOPT_STDOPTS, MOPT_UPDATE, { NULL } }; ... mntflags = 0; ... getmntopts(options, mopts, &mntflags) ... DIAGNOSTICS
The getmntopts function displays an error message and exits if an unrecognized option is encountered. SEE ALSO
err(3), mount(8) HISTORY
The getmntopts function appeared in 4.4BSD. 4.4 Berkeley Distribution January 16, 1996 GETMNTOPTS(3)

Check Out this Related Man Page

CHFLAGS(1)						    BSD General Commands Manual 						CHFLAGS(1)

NAME
chflags -- change file flags SYNOPSIS
chflags [-R [-H | -L | -P]] flags file ... DESCRIPTION
The chflags utility modifies the file flags of the listed files as specified by the flags operand. The options are as follows: -H If the -R option is specified, symbolic links on the command line are followed. (Symbolic links encountered in the tree traversal are not followed.) -L If the -R option is specified, all symbolic links are followed. -P If the -R option is specified, no symbolic links are followed. This is the default. -R Change the file flags for the file hierarchies rooted in the files instead of just the files themselves. The flags are specified as an octal number or a comma separated list of keywords. The following keywords are currently defined: arch set the archived flag (super-user only) opaque set the opaque flag (owner or super-user only) nodump set the nodump flag (owner or super-user only) sappnd set the system append-only flag (super-user only) schg set the system immutable flag (super-user only) sunlnk set the system undeletable flag (super-user only) uappnd set the user append-only flag (owner or super-user only) uchg set the user immutable flag (owner or super-user only) uunlnk set the user undeletable flag (owner or super-user only) archived, sappend, schange, simmutable, uappend, uchange, uimmutable, sunlink, uunlink aliases for the above Putting the letters ``no'' before an option causes the flag to be turned off. For example: nouchg the immutable bit should be cleared Symbolic links do not have flags, so unless the -H or -L option is set, chflags on a symbolic link always succeeds and has no effect. The -H, -L and -P options are ignored unless the -R option is specified. In addition, these options override each other and the command's actions are determined by the last one specified. You can use "ls -lo" to see the flags of existing files. DIAGNOSTICS
The chflags utility exits 0 on success, and >0 if an error occurs. SEE ALSO
ls(1), chflags(2), stat(2), fts(3), symlink(7) HISTORY
The chflags command first appeared in 4.4BSD. BSD
May 2, 1995 BSD

Featured Tech Videos