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GLOB(3) Library Functions Manual GLOB(3)
NAME
glob, globfree, glob_pattern_p - 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 *, int), glob_t * restrict pglob);
void
globfree(glob_t *pglob);
int
glob_pattern_p(const char *pattern, int quote);
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 {
size_t gl_pathc; /* count of total paths so far */
size_t gl_matchc; /* count of paths matching pattern */
size_t 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 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 one
level of backslash escapes removed, the number of total
pathnames set to 1, and the number of matched pathnames
set to 0.
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 (csh(1) does
the same thing to ease typing of find(1) patterns).
GLOB_LIMIT Limit the amount of memory used to store matched
strings to 64K, the number of stat(2) calls to 128, 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
*/../*/..
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_NOESCAPE Disable the use of the backslash (`\') character for
quoting.
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_NO_DOTDIRS Hide `.' and `..' from metacharacter matches,
regardless of whether GLOB_PERIOD is set and whether
the pattern component begins with a literal period.
GLOB_PERIOD Allow metacharacters to match a leading period in a
filename.
GLOB_STAR Indicates that two adjacent * characters will do a
recursive match in all subdirs, without following
symbolic links and three adjacent * characters will
also follow symbolic links.
GLOB_TILDE Expand patterns that start with `~' to user name home
directories. If the user with the given user name (or
the user id of the current user in the case of "~/") is
not found, the original pattern is returned.
GLOB_TILDE_CHECK When used with GLOB_TILDE and the user name or the user
id is not found, then GLOB_NOMATCH is returned instead
of the original pattern.
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().
The glob_pattern_p() returns 1 if the pattern has any special characters
that glob() will interpret and 0 otherwise. If the quote argument is
non-zero, then backslash quoted characters are ignored.
The historical GLOB_QUOTE flag is no longer supported. Per IEEE Std
1003.2-1992 ("POSIX.2"), backslash escaping of special characters is the
default behaviour; it may be disabled by specifying the GLOB_NOESCAPE
flag.
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.
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_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 does not match any existing pathname, and
GLOB_NOCHECK was not set in flags.
GLOB_NOSPACE An attempt to allocate memory failed, or if errno was 0
GLOB_LIMIT was specified in the flags and ARG_MAX
patterns were matched.
The historical GLOB_ABEND return constant is no longer supported.
Portable applications should use the GLOB_ABORTED constant instead.
The arguments pglob->gl_pathc and pglob->gl_pathv are still set as
specified above.
ENVIRONMENT
HOME If defined, used as the home directory of the current user in tilde
expansions.
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);
SEE ALSO
sh(1), fnmatch(3), regexp(3), glob(7)
STANDARDS
The glob() function is expected to be IEEE Std 1003.2 ("POSIX.2")
compatible with the exception that the flags GLOB_ALTDIRFUNC, GLOB_BRACE,
GLOB_LIMIT, GLOB_MAGCHAR, GLOB_NOESCAPE, GLOB_NOMAGIC, GLOB_NO_DOTDIRS,
GLOB_PERIOD, GLOB_STAR, GLOB_TILDE, and the fields gl_matchc and gl_flags
should not be used by applications striving for strict POSIX conformance.
HISTORY
The glob() and globfree() functions first appeared in 4.4BSD. The
glob_pattern_p() function is modelled after the one found in glibc.
BUGS
Patterns longer than MAXPATHLEN may cause unchecked 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).
NetBSD 10.99 May 28, 2019 NetBSD 10.99