glob



GLOB(3)                   OpenBSD Programmer's Manual                  GLOB(3)


NAME

     glob, globfree - generate pathnames matching a pattern


SYNOPSIS

     #include <glob.h>

     int
     glob(const char *pattern, int flags, const int (*errfunc)(const char *,
     int), glob_t *pglob);

     void
     globfree(glob_t *pglob);


DESCRIPTION

     The glob() function is a pathname generator that implements the rules for
     file name pattern matching used by the shell.

     The include file <glob.h> defines the structure type glob_t, which
     contains at least the following fields:

           typedef struct {
                   int gl_pathc;    /* count of total paths so far */
                   int gl_matchc;   /* count of paths matching pattern */
                   int gl_offs;     /* reserved at beginning of gl_pathv */
                   int gl_flags;    /* returned flags */
                   char **gl_pathv; /* list of paths matching pattern */
           } glob_t;

     The argument pattern is a pointer to a pathname pattern to be expanded.
     glob() matches all accessible pathnames against the pattern and creates a
     list of the pathnames that match.  In order to have access to a pathname,
     glob() requires search permission on every component of a path except the
     last and read permission on each directory of any filename component of
     pattern that contains any of the special characters `*', `?', or `['.

     The number of matched pathnames is stored in the gl_pathc field, and a
     pointer to a list of pointers to pathnames in the gl_pathv field.  The
     first pointer after the last pathname is NULL.  If the pattern does not
     match any pathnames, the returned number of matched paths is set to zero.

     It is the caller's responsibility to create the structure pointed to by
     pglob.  The glob() function allocates other space as needed, including
     the memory pointed to by gl_pathv.

     The argument flags is used to modify the behavior of glob().  The value
     of flags is the bitwise inclusive OR of any of the following values
     defined in <glob.h>:

     GLOB_APPEND      Append pathnames generated to the ones from a previous
                      call (or calls) to glob().  The value of gl_pathc will
                      be the total matches found by this call and the previous
                      call(s).  The pathnames are appended to, not merged with
                      the pathnames returned by the previous call(s).  Between
                      calls, the caller must not change the setting of the
                      GLOB_DOOFFS flag, nor change the value of gl_offs when
                      GLOB_DOOFFS is set, nor (obviously) call globfree() for
                      pglob.

     GLOB_DOOFFS      Make use of the gl_offs field.  If this flag is set,
                      gl_offs is used to specify how many null pointers to
                      prepend to the beginning of the gl_pathv field.  In
                      other words, gl_pathv will point to gl_offs null
                      pointers, followed by gl_pathc pathname pointers,
                      followed by a null pointer.

     GLOB_ERR         Causes glob() to return when it encounters a directory
                      that it cannot open or read.  Ordinarily, glob()
                      continues to find matches.

     GLOB_MARK        Each pathname that is a directory that matches pattern
                      has a slash appended.

     GLOB_NOCHECK     If pattern does not match any pathname, then glob()
                      returns a list consisting of only pattern, with the
                      number of total pathnames set to 1, and the number of
                      matched pathnames set to 0.

     GLOB_NOESCAPE    Normally, every occurrence of a backslash (`\') followed
                      by a character in pattern is replaced by that character.
                      This is done to negate any special meaning for the
                      character.  If the GLOB_NOESCAPE flag is set, a
                      backslash character is treated as an ordinary character.

     GLOB_NOSORT      By default, the pathnames are sorted in ascending ASCII
                      order; this flag prevents that sorting (speeding up
                      glob()).

     The following values may also be included in flags, however, they are
     non-standard extensions to IEEE Std 1003.2 (``POSIX.2'').

     GLOB_ALTDIRFUNC  The following additional fields in the pglob structure
                      have been initialized with alternate functions for
                      glob() to use to open, read, and close directories and
                      to get stat information on names found in those
                      directories:

                              void *(*gl_opendir)(const char *);
                              struct dirent *(*gl_readdir)(void *);
                              void (*gl_closedir)(void *);
                              int (*gl_lstat)(const char *, struct stat *);
                              int (*gl_stat)(const char *, struct stat *);

                      This extension is provided to allow programs such as
                      restore(8) to provide globbing from directories stored
                      on tape.

     GLOB_BRACE       Pre-process the pattern string to expand `{pat,pat,...}'
                      strings like csh(1).  The pattern `{}' is left
                      unexpanded for historical reasons.  (csh(1) does the
                      same thing to ease typing of find(1) patterns.)

     GLOB_KEEPSTAT    Retain a copy of the stat(2) information retrieved for
                      matching paths in the gl_statv array:

                            struct stat **gl_statv;

                      This option may be used to avoid lstat(2) lookups in
                      cases where they are expensive.

     GLOB_MAGCHAR     Set by the glob() function if the pattern included
                      globbing characters.  See the description of the usage
                      of the gl_matchc structure member for more details.

     GLOB_NOMAGIC     Is the same as GLOB_NOCHECK but it only appends the
                      pattern if it does not contain any of the special
                      characters `*', `?', or `['.  GLOB_NOMAGIC is provided
                      to simplify implementing the historic csh(1) globbing
                      behavior and should probably not be used anywhere else.

     GLOB_QUOTE       This option has no effect and is included for backwards
                      compatibility with older sources.

     GLOB_TILDE       Expand patterns that start with `~' to user name home
                      directories.

     GLOB_LIMIT       Limit the amount of memory used to store matched strings
                      to 64K, the number of stat(2) calls to 2048, and the
                      number of readdir(3) calls to 16K.  This option should
                      be set for programs that can be coerced to a denial of
                      service attack via patterns that expand to a very large
                      number of matches, such as a long string of `*/../*/..'.

     If, during the search, a directory is encountered that cannot be opened
     or read and errfunc is non-null, glob() calls (*errfunc)(path, errno).
     This may be unintuitive: a pattern like ``*/Makefile'' will try to
     stat(2) ``foo/Makefile'' even if ``foo'' is not a directory, resulting in
     a call to errfunc.  The error routine can suppress this action by testing
     for ENOENT and ENOTDIR; however, the GLOB_ERR flag will still cause an
     immediate return when this happens.

     If errfunc returns non-zero, glob() stops the scan and returns
     GLOB_ABORTED after setting gl_pathc and gl_pathv to reflect any paths
     already matched.  This also happens if an error is encountered and
     GLOB_ERR is set in flags, regardless of the return value of errfunc, if
     called.  If GLOB_ERR is not set and either errfunc is NULL or errfunc
     returns zero, the error is ignored.

     The globfree() function frees any space associated with pglob from a
     previous call(s) to glob().


RETURN VALUES

     On successful completion, glob() returns zero.  In addition the fields of
     pglob contain the values described below:

     gl_pathc      Contains the total number of matched pathnames so far.
                   This includes other matches from previous invocations of
                   glob() if GLOB_APPEND was specified.

     gl_matchc     Contains the number of matched pathnames in the current
                   invocation of glob().

     gl_flags      Contains a copy of the flags parameter with the bit
                   GLOB_MAGCHAR set if pattern contained any of the special
                   characters `*', `?', or `[', cleared if not.

     gl_pathv      Contains a pointer to a null-terminated list of matched
                   pathnames.  However, if gl_pathc is zero, the contents of
                   gl_pathv are undefined.

     gl_statv      If the GLOB_KEEPSTAT flag was set, gl_statv contains a
                   pointer to a null-terminated list of matched stat(2)
                   objects corresponding to the paths in gl_pathc.

     If glob() terminates due to an error, it sets errno and returns one of
     the following non-zero constants, which are defined in the include file
     <glob.h>:

     GLOB_NOSPACE  An attempt to allocate memory failed, or if errno was 0
                   GLOB_LIMIT was specified in the flags and ARG_MAX or more
                   patterns were matched.

     GLOB_ABORTED  The scan was stopped because an error was encountered and
                   either GLOB_ERR was set, or (*errfunc)() returned non-zero.

     GLOB_NOMATCH  The pattern did not match a pathname and GLOB_NOCHECK was
                   not set.

     GLOB_NOSYS    The requested function is not supported by this version of
                   glob().

     The arguments pglob->gl_pathc and pglob->gl_pathv are still set as
     specified above.


EXAMPLES

     A rough equivalent of `ls -l *.c *.h' can be obtained with the following
     code:

           glob_t g;

           g.gl_offs = 2;
           glob("*.c", GLOB_DOOFFS, NULL, &g);
           glob("*.h", GLOB_DOOFFS | GLOB_APPEND, NULL, &g);
           g.gl_pathv[0] = "ls";
           g.gl_pathv[1] = "-l";
           execvp("ls", g.gl_pathv);


ERRORS

     The glob() function may fail and set errno for any of the errors
     specified for the library routines stat(2), closedir(3), opendir(3),
     readdir(3), malloc(3), and free(3).


SEE ALSO

     sh(1), fnmatch(3), regex(3), glob(7)


STANDARDS

     The glob() function is expected to conform to IEEE Std 1003.2
     (``POSIX.2'') and X/Open Portability Guide Issue 4, Version 2
     (``XPG4.2'').  Note, however, that the flags GLOB_ALTDIRFUNC, GLOB_BRACE,
     GLOB_KEEPSTAT, GLOB_MAGCHAR, GLOB_NOMAGIC, GLOB_QUOTE, GLOB_TILDE, and
     GLOB_LIMIT and the fields gl_matchc, gl_statv and gl_flags should not be
     used by applications striving for strict standards conformance.


HISTORY

     The glob() and globfree() functions first appeared in 4.4BSD.


BUGS

     Patterns longer than MAXPATHLEN may cause unchecked errors.

OpenBSD 5.4                      June 5, 2013                      OpenBSD 5.4

[Unix Hosting | Open-Source | Contact Us]
[Engineering & Automation | Software Development | Server Applications]