glob()

NAME

glob(), globfree() - generate pathnames matching a pattern

SYNOPSIS

#include <glob.h>

int glob (const char *pattern, int flags, const int (*errfunc)(const char *, int), glob_t *pglob) void globfree (glob_t *pglob)

DESCRIPTION

The glob(3) function is a pathname generator that implements the rules for file name pattern matching used by the standard 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(3) 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(3) 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(3) 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(3) 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(3). 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(3). 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(3) 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(3) to return when it encounters a directory that it cannot open or read. Ordinarily, glob(3) 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(3) returns a list consisting of only pattern, with the number of total pathnames is set to 1, and the number of matched pathnames set to 0. If GLOB_QUOTE is set, its effect is present in the pattern returned.
GLOB_NOSORT
By default, the pathnames are sorted in ascending ASCII order; this flag prevents that sorting (speeding up glob(3)).

The following values may also be included in flags, however, they are non-standard extensions to

GLOB_ALTDIRFUNC
The following additional fields in the pglob structure have been initialized with alternate functions for glob(3) 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() to provide globbing from directories stored on tape.

GLOB_BRACE
Pre-process the pattern string to expand {pat,pat,...} strings like Csh(1)The {} is left unexpanded for historical reasons (Csh(1) does the same thing to ease typing of find() patterns).
GLOB_MAGCHAR
Set by the glob(3) 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(3) globbing behavior and should probably not be used anywhere else.
GLOB_QUOTE
Use the backslash (\ character for quoting: every occurrence of a backslash followed by a character in the pattern is replaced by that character, avoiding any special interpretation of the character.
GLOB_TILDE
Expand patterns that start with ~ to user name home directories.

If, during the search, a directory is encountered that cannot be opened or read and errfunc is non-NULL, glob(3) calls (*errfunc 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(3) stops the scan and returns GLOB_ABEND 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(3) function frees any space associated with pglob from a previous call(s) to glob(3).

RETURN VALUES

On successful completion, glob(3) 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(3) if GLOB_APPEND was specified.
gl_matchc
contains the number of matched pathnames in the current invocation of glob(3).
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(3) 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_NOSPACE
An attempt to allocate memory failed.
GLOB_ABEND
The scan was stopped because an error was encountered and either GLOB_ERR was set or (*errfunc returned non-zero.

The arguments pglob->gl_pathc and pglob->gl_pathv are still set as specified above.

EXAMPLE

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);

NOTE

The file name matching implemented by glob(3) is the basic set of matches specified by the Open Group's specification. It treats the characters *, ?, and [ as special. It does not support all of the special matches that are part of the KornShell (such as *(), for example).

SEE ALSO

sh(1)

fnmatch(3)

regexec(3)

BUGS

Patterns longer than {MAXPATHLEN} may cause unchecked errors.

The glob(3) argument may fail and set errno for any of the errors specified for the library routines stat(2), closedir(3), opendir(3), readdir(2), malloc(3), and free(3).