February 22, 2008 GLOB 3

### NAME

glob, globfree - generate pathnames matching a pattern

### LIBRARY

Standard C Library (libc, -lc)

### SYNOPSIS

```int` glob(```const char * restrict pattern``, int flags``, const int (*errfunc)(const char *, int)``, 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 {
            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 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 ease typing of find(1) patterns (csh(1) does the same thing to.)

```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_NOESCAPE`
  Disable the use of the backslash (`\') character for quoting.

```GLOB_TILDE`
  Expand patterns that start with `~' to user name home directories.

```GLOB_LIMIT`
  Limit the amount of memory used by matches to ```ARG_MAX`. 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_PERIOD`
  Allow metacharacters to match a leading period in a filename.

```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.

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 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)

### 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_MAGCHAR`, ```GLOB_NOMAGIC`, ```GLOB_TILDE`, and ```GLOB_LIMIT` 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.

### 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).