GLOB(3)

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).

May 28, 2019 | NetBSD 10.1