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PROLOG

       This  manual  page  is part of the POSIX Programmer's Manual.  The Linux implementation of
       this interface may differ (consult the corresponding Linux  manual  page  for  details  of
       Linux behavior), or the interface may not be implemented on Linux.

NAME

       glob, globfree — generate pathnames matching a pattern

SYNOPSIS

       #include <glob.h>

       int glob(const char *restrict pattern, int flags,
           int(*errfunc)(const char *epath, int eerrno),
           glob_t *restrict pglob);
       void globfree(glob_t *pglob);

DESCRIPTION

       The  glob() function is a pathname generator that shall implement the rules defined in the
       Shell and Utilities volume of POSIX.1‐2017, Section 2.13, Pattern Matching Notation,  with
       optional  support  for  rule  3 in the Shell and Utilities volume of POSIX.1‐2017, Section
       2.13.3, Patterns Used for Filename Expansion.

       The structure type glob_t is defined in <glob.h>  and  includes  at  least  the  following
       members:

                ┌──────────────┬──────────────┬─────────────────────────────────────────┐
                │Member TypeMember NameDescription               │
                ├──────────────┼──────────────┼─────────────────────────────────────────┤
                │size_tgl_pathc      │ Count of paths matched by pattern.      │
                │char **gl_pathv      │ Pointer to a list of matched pathnames. │
                │size_tgl_offs       │ Slots  to  reserve  at the beginning of │
                │              │              │ gl_pathv.                               │
                └──────────────┴──────────────┴─────────────────────────────────────────┘
       The argument pattern is a pointer to  a  pathname  pattern  to  be  expanded.  The  glob()
       function  shall  match all accessible pathnames against this pattern and develop a list of
       all 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 following  special
       characters: '*', '?', and '['.

       The glob() function shall store the number of matched pathnames into pglob->gl_pathc and a
       pointer to a list of pointers to pathnames into pglob->gl_pathv. The pathnames shall be in
       sort  order  as  defined  by  the current setting of the LC_COLLATE category; see the Base
       Definitions volume of POSIX.1‐2017, Section 7.3.2, LC_COLLATE.  The  first  pointer  after
       the  last  pathname  shall be a null pointer. If the pattern does not match any pathnames,
       the returned number of matched paths is set to 0, and the contents of pglob->gl_pathv  are
       implementation-defined.

       It is the caller's responsibility to create the structure pointed to by pglob.  The glob()
       function shall allocate other  space  as  needed,  including  the  memory  pointed  to  by
       gl_pathv.   The  globfree()  function  shall  free  any space associated with pglob from a
       previous call to glob().

       The flags argument is used to control the behavior of glob().  The value  of  flags  is  a
       bitwise-inclusive  OR  of  zero  or  more of the following constants, which are defined in
       <glob.h>:

       GLOB_APPEND   Append pathnames generated to the ones from a previous call to glob().

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

       GLOB_ERR      Cause 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 shall have a  <slash>
                     appended.

       GLOB_NOCHECK  Supports  rule  3 in the Shell and Utilities volume of POSIX.1‐2017, Section
                     2.13.3, Patterns Used for Filename Expansion.  If pattern does not match any
                     pathname,  then  glob()  shall return a list consisting of only pattern, and
                     the number of matched pathnames is 1.

       GLOB_NOESCAPE Disable backslash escaping.

       GLOB_NOSORT   Ordinarily, glob() sorts the matching pathnames  according  to  the  current
                     setting  of  the  LC_COLLATE  category;  see  the Base Definitions volume of
                     POSIX.1‐2017, Section 7.3.2, LC_COLLATE.  When this flag is used, the  order
                     of pathnames returned is unspecified.

       The  GLOB_APPEND  flag  can  be  used to append a new set of pathnames to those found in a
       previous call to glob().  The following rules apply to applications when two or more calls
       to  glob()  are  made  with  the  same  value  of  pglob  and without intervening calls to
       globfree():

        1. The first such call shall not set GLOB_APPEND. All subsequent calls shall set it.

        2. All the calls shall set GLOB_DOOFFS, or all shall not set it.

        3. After the second call, pglob->gl_pathv points to a list containing the following:

            a. Zero or more null pointers, as specified by GLOB_DOOFFS and pglob->gl_offs.

            b. Pointers to the pathnames that were in the pglob->gl_pathv list before  the  call,
               in the same order as before.

            c. Pointers  to  the  new  pathnames  generated  by the second call, in the specified
               order.

        4. The count returned in pglob->gl_pathc shall be the total number of pathnames from  the
           two calls.

        5. The  application can change any of the fields after a call to glob().  If it does, the
           application shall reset them to the original value before a subsequent call, using the
           same pglob value, to globfree() or glob() with the GLOB_APPEND flag.

       If,  during  the  search,  a  directory  is  encountered that cannot be opened or read and
       errfunc is not a null pointer, glob() calls (()*errfunc ) with two arguments:

        1. The epath argument is a pointer to the path that failed.

        2. The eerrno argument is the value of errno from  the  failure,  as  set  by  opendir(),
           readdir(), or stat().  (Other values may be used to report other errors not explicitly
           documented for those functions.)

       If (()*errfunc ) is called and returns non-zero, or if the GLOB_ERR flag is set in  flags,
       glob()  shall stop the scan and return GLOB_ABORTED after setting gl_pathc and gl_pathv in
       pglob to reflect the paths already scanned. If GLOB_ERR is not set and either errfunc is a
       null pointer or (()*errfunc ) returns 0, the error shall be ignored.

       The glob() function shall not fail because of large files.

RETURN VALUE

       Upon  successful  completion,  glob()  shall  return 0. The argument pglob->gl_pathc shall
       return the number of matched pathnames and the argument pglob->gl_pathv  shall  contain  a
       pointer   to  a  null-terminated  list  of  matched  and  sorted  pathnames.  However,  if
       pglob->gl_pathc is 0, the content of pglob->gl_pathv is undefined.

       The globfree() function shall not return a value.

       If glob() terminates due to an error, it  shall  return  one  of  the  non-zero  constants
       defined  in  <glob.h>.  The arguments pglob->gl_pathc and pglob->gl_pathv are still set as
       defined above.

ERRORS

       The glob() function shall fail and return the corresponding value if:

       GLOB_ABORTED  The scan was stopped because GLOB_ERR was set or (()*errfunc ) returned non-
                     zero.

       GLOB_NOMATCH  The  pattern  does not match any existing pathname, and GLOB_NOCHECK was not
                     set in flags.

       GLOB_NOSPACE  An attempt to allocate memory failed.

       The following sections are informative.

EXAMPLES

       One use of the GLOB_DOOFFS flag is by applications that build an  argument  list  for  use
       with  execv(),  execve(), or execvp().  Suppose, for example, that an application wants to
       do the equivalent of:

           ls -l *.c

       but for some reason:

           system("ls -l *.c")

       is not acceptable. The application could obtain approximately the same  result  using  the
       sequence:

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

       Using the same example:

           ls -l *.c *.h

       could be approximately simulated using GLOB_APPEND as follows:

           globbuf.gl_offs = 2;
           glob("*.c", GLOB_DOOFFS, NULL, &globbuf);
           glob("*.h", GLOB_DOOFFS|GLOB_APPEND, NULL, &globbuf);
           ...

APPLICATION USAGE

       This  function  is  not provided for the purpose of enabling utilities to perform pathname
       expansion on their arguments, as this operation is performed by the shell,  and  utilities
       are  explicitly  not  expected to redo this. Instead, it is provided for applications that
       need to do pathname expansion on strings obtained from other sources, such  as  a  pattern
       typed by a user or read from a file.

       If a utility needs to see if a pathname matches a given pattern, it can use fnmatch().

       Note  that  gl_pathc and gl_pathv have meaning even if glob() fails. This allows glob() to
       report partial results in the event of an error. However, if gl_pathc is  0,  gl_pathv  is
       unspecified even if glob() did not return an error.

       The  GLOB_NOCHECK  option  could be used when an application wants to expand a pathname if
       wildcards are specified, but wants to treat the pattern as just a string otherwise. The sh
       utility might use this for option-arguments, for example.

       The  new pathnames generated by a subsequent call with GLOB_APPEND are not sorted together
       with the previous pathnames.  This  mirrors  the  way  that  the  shell  handles  pathname
       expansion when multiple expansions are done on a command line.

       Applications that need tilde and parameter expansion should use wordexp().

RATIONALE

       It  was  claimed  that  the  GLOB_DOOFFS flag is unnecessary because it could be simulated
       using:

           new = (char **)malloc((n + pglob->gl_pathc + 1)
                  * sizeof(char *));
           (void) memcpy(new+n, pglob->gl_pathv,
                  pglob->gl_pathc * sizeof(char *));
           (void) memset(new, 0, n * sizeof(char *));
           free(pglob->gl_pathv);
           pglob->gl_pathv = new;

       However, this assumes that the  memory  pointed  to  by  gl_pathv  is  a  block  that  was
       separately  created  using  malloc().   This  is  not necessarily the case. An application
       should make no assumptions about  how  the  memory  referenced  by  fields  in  pglob  was
       allocated.  It  might have been obtained from malloc() in a large chunk and then carved up
       within glob(), or it might have been created using a different memory allocator. It is not
       the intent of the standard developers to specify or imply how the memory used by glob() is
       managed.

       The GLOB_APPEND flag would be used when an application wants to expand  several  different
       patterns into a single list.

FUTURE DIRECTIONS

       None.

SEE ALSO

       exec, fdopendir(), fnmatch(), fstatat(), readdir(), Section 2.6, Word Expansions

       The Base Definitions volume of POSIX.1‐2017, Section 7.3.2, LC_COLLATE, <glob.h>

COPYRIGHT

       Portions  of  this  text  are  reprinted  and  reproduced in electronic form from IEEE Std
       1003.1-2017, Standard for Information Technology -- Portable  Operating  System  Interface
       (POSIX),  The  Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by
       the Institute of Electrical and Electronics Engineers, Inc and The  Open  Group.   In  the
       event  of  any  discrepancy  between this version and the original IEEE and The Open Group
       Standard, the original IEEE and The Open Group  Standard  is  the  referee  document.  The
       original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

       Any  typographical  or  formatting errors that appear in this page are most likely to have
       been introduced during the conversion of the source files to man page  format.  To  report
       such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .