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
Theglob()
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 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 theGLOB_DOOFFSflag, nor change the value of gl_offs whenGLOB_DOOFFSis set, nor (obviously) callglobfree() for pglob. GLOB_DOOFFS- Make use of the gl_offs field. If this flag is set,
gl_offs is used to specify how many
NULLpointers to prepend to the beginning of the gl_pathv field. In other words, gl_pathv will point to gl_offsNULLpointers, followed by gl_pathc pathname pointers, followed by aNULLpointer. 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 is set to 1, and the number of matched pathnames set to 0. IfGLOB_QUOTEis 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()).
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_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_NOCHECKbut it only appends the pattern if it does not contain any of the special characters ``*'', ``?'' or ``[''.GLOB_NOMAGICis provided to simplify implementing the historic csh(1) 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() 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_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()
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() ifGLOB_APPENDwas 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_MAGCHARset 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_NOSPACE- An attempt to allocate memory failed.
GLOB_ABEND- The scan was stopped because an error was encountered and either
GLOB_ERRwas 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);
SEE ALSO
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_QUOTE,
and 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.
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).