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GLOB(3P)                   POSIX Programmer's Manual                  GLOB(3P)



PROLOG
       This manual page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may dif-
       fer (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 IEEE Std 1003.1-2001, Section 2.13, Pattern Matching Notation, with optional support for  rule  3  in
       the Shell and Utilities volume of IEEE Std 1003.1-2001, 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 Type Member Name Description
                           size_t      gl_pathc    Count of paths matched by pattern.
                           char **     gl_pathv    Pointer to a list of matched pathnames.
                           size_t      gl_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 set-
       ting  of  the  LC_COLLATE  category;  see  the  Base Definitions volume of IEEE Std 1003.1-2001, 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 imple-
       mentation-defined.

       It is the caller's responsibility to create the structure pointed to by pglob. The glob() function shall  allo-
       cate  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 point-
              ers 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 IEEE Std 1003.1-2001, Section 2.13.3, Patterns Used
              for Filename Expansion. If pattern does not match any pathname, then glob() shall return a list consist-
              ing 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 cate-
              gory; see the Base Definitions volume of IEEE Std 1003.1-2001, 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  speci-
       fied, but wants to treat the pattern as just a string otherwise. The sh utility might use this for option-argu-
       ments, 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  mal-
       loc().  This is not necessarily the case. An application should make no assumptions about how the memory refer-
       enced 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(),    fnmatch(),   opendir(),   readdir(),   stat(),   wordexp(),   the   Base   Definitions   volume   of
       IEEE Std 1003.1-2001, <glob.h>, the Shell and Utilities volume of IEEE Std 1003.1-2001

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Stan-
       dard  for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifica-
       tions Issue 6, Copyright (C) 2001-2003 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 Stan-
       dard, 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 .



IEEE/The Open Group                  2003                             GLOB(3P)