PROLOG | NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLES | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT

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

PROLOG         top

       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         top

       glob, globfree — generate pathnames matching a pattern

SYNOPSIS         top

       #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         top

       The glob() function is a pathname generator that shall implement the
       rules defined in the Shell and Utilities volume of POSIX.1‐2008,
       Section 2.13, Pattern Matching Notation, with optional support for
       rule 3 in the Shell and Utilities volume of POSIX.1‐2008, 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 setting of the LC_COLLATE category; see the Base
       Definitions volume of POSIX.1‐2008, 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.1‐2008, 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.1‐2008, 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         top

       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         top

       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         top

       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         top

       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         top

       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         top

       None.

SEE ALSO         top

       exec(1p), fdopendir(3p), fnmatch(3p), fstatat(3p), readdir(3p),
       Section 2.6, Word Expansions

       The Base Definitions volume of POSIX.1‐2008, Section 7.3.2,
       LC_COLLATE, glob.h(0p)

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2013 Edition, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The Open
       Group Base Specifications Issue 7, Copyright (C) 2013 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
       applied.) 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.unix.org/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 .

IEEE/The Open Group                 2013                            GLOB(3P)

Pages that refer to this page: glob.h(0p)fnmatch(3p)regcomp(3p)wordexp(3p)