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BSD 2.11 - man page for getmntopts (bsd section 3)

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GETMNTOPTS(3)									    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 discovered, 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 program 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)
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