GLOB(3) BSD Library Functions Manual GLOB(3)
NAME
glob, globfree -- generate pathnames matching a pattern
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <glob.h>
int
glob(const char *restrict pattern, int flags, int (*errfunc)(const char *epath, int eerno),
glob_t *restrict 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. The glob() argument 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 glob() argument stores the number of matched pathnames into the gl_pathc field, and a pointer to a
list of pointers to pathnames into 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 inclu-sive inclusive
sive 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 (obvi-ously) (obviously)
ously) 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 path-names pathnames
names set to 0. The effect of backslash escaping is present in the pattern returned.
GLOB_NOESCAPE By default, a backslash (`\') character is used to escape the following character in
the pattern, avoiding any special interpretation of the character. If GLOB_NOESCAPE
is set, backslash escaping is disabled.
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 * name);
struct dirent *(*gl_readdir)(void *);
void (*gl_closedir)(void *);
int (*gl_lstat)(const char *name, struct stat *st);
int (*gl_stat)(const char *name, struct stat *st);
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 (and csh(1) does the same thing
to ease typing of find(1) patterns).
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_TILDE Expand patterns that start with `~' to user name home directories.
GLOB_LIMIT Limit the total number of returned pathnames to the value provided in gl_matchc
(default ARG_MAX). This option should be set for programs that can be coerced into 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 argument 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.
If glob() terminates due to an error, it sets errno and returns one of the following non-zero con-stants, constants,
stants, 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 pglob->gl_matchc 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.
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);
CAVEATS
The glob() function will not match filenames that begin with a period unless this is specifically
requested (e.g., by ".*").
SEE ALSO
sh(1), fnmatch(3), regexp(3)
STANDARDS
The current implementation of the glob() function does not conform to IEEE Std 1003.2 (``POSIX.2'').
Collating symbol expressions, equivalence class expressions and character class expressions are not
supported.
The flags GLOB_ALTDIRFUNC, GLOB_BRACE, GLOB_LIMIT, GLOB_MAGCHAR, GLOB_NOMAGIC, and GLOB_TILDE, and the
fields gl_matchc and gl_flags are extensions to the POSIX standard and should not be used by applica-tions applications
tions striving for strict conformance.
HISTORY
The glob() and globfree() functions first appeared in 4.4BSD.
BUGS
Patterns longer than MAXPATHLEN may cause unchecked errors.
The glob() argument 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).
BSD September 1, 2004 BSD
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