glob(3C)
NAME
glob, globfree - generate path names matching a pattern
SYNOPSIS
#include <glob.h>
int glob(const char *pattern, int flags, int(*errfunc)(const
char *epath int eerrno), glob_t *pglob);
void globfree(glob_t *pglob);
DESCRIPTION
The glob() function is a path name generator.
The globfree() function frees any memory allocated by glob()
associated with pglob.
pattern Argument
The argument pattern is a pointer to a path name pattern to
be expanded. The glob() function matches all accessible path
names against this pattern and develops a list of all path
names that match. In order to have access to a path name,
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 following special characters:
* ? [
pglob Argument
The structure type glob_t is defined in the header <glob.h>
and includes at least the following members:
size_t gl_pathc; /* count of paths matched by pattern */
char **gl_pathv; /* pointer to list of matched path names */
size_t gl_offs; /* slots to reserve at beginning of gl_pathv */
The glob() function stores the number of matched path names
into pglob->gl_pathc and a pointer to a list of pointers to
path names into pglob->gl_pathv. The path names are in sort
order as defined by the current setting of the LC_COLLATE
category. The first pointer after the last path name is a
NULL pointer. If the pattern does not match any path names,
the returned number of matched paths is set to 0, and the
contents of pglob->gl_pathv are implementation-dependent.
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 globfree() function frees any space associated
with pglob from a previous call to glob().
flags Argument
The flags argument is used to control the behavior of
glob(). The value of flags is a bitwise inclusive OR of zero
or more of the following constants, which are defined in the
header <glob.h>:
GLOB_APPEND
Append path names generated to the ones from a previ-
ous call to glob().
GLOB_DOOFFS
Make use of pglob->gl_offs. If this flag is set,
pglob->gl_offs is used to specify how many NULL
pointers to add to the beginning of pglob->gl_pathv.
In other words, pglob->gl_pathv will point to
pglob->gl_offs NULL pointers, followed by
pglob->gl_pathc path name 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() con-
tinues to find matches.
GLOB_MARK
Each path name that is a directory that matches pat-
tern has a slash appended.
GLOB_NOCHECK
If pattern does not match any path name, then glob()
returns a list consisting of only pattern, and the
number of matched path names is 1.
GLOB_NOESCAPE
Disable backslash escaping.
GLOB_NOSORT
Ordinarily, glob() sorts the matching path names
according to the current setting of the LC_COLLATE
category. When this flag is used the order of path
names returned is unspecified.
The GLOB_APPEND flag can be used to append a new set of path
names to those found in a previous call to glob(). The fol-
lowing rules apply when two or more calls to glob() are made
with the same value of pglob and without intervening calls
to globfree():
1. The first such call must not set GLOB_APPEND. All subse-
quent calls must set it.
2. All the calls must set GLOB_DOOFFS, or all must not set
it.
3. After the second call, pglob->gl_pathv points to a list
containing the following:
a. Zero or more NULL pointers, as specified by
GLOB_DOOFFS and pglob->gl_offs.
b. Pointers to the path names that were in the
pglob->gl_pathv list before the call, in the same
order as before.
c. Pointers to the new path names generated by the second
call, in the specified order.
4. The count returned in pglob->gl_pathc will be the total
number of path names from the two calls.
5. The application can change any of the fields after a call
to glob(). If it does, it must reset them to the original
value before a subsequent call, using the same pglob
value, to globfree() or glob() with the GLOB_APPEND flag.
errfunc and epath Arguments
If, during the search, a directory is encountered that can-
not be opened or read and errfunc is not a NULL pointer,
glob() calls (*errfunc) with two arguments:
1. The epath argument is a pointer to the path that failed.
2. The eerrno argument is the value of errno from the
failure, as set by the opendir(3C), readdir(3C) or
stat(2) functions. (Other values may be used to report
other errors not explicitly documented for those func-
tions.)
The following constants are defined as error return values
for glob():
GLOB_ABORTED
The scan was stopped because GLOB_ERR was set or
(*errfunc) returned non-zero.
GLOB_NOMATCH
The pattern does not match any existing path name, and
GLOB_NOCHECK was not set in flags.
GLOG_NOSPACE
An attempt to allocate memory failed.
If (*errfunc) is called and returns non-zero, or if the
GLOB_ERR flag is set in flags, glob() stops the scan and
returns GLOB_ABORTED after setting gl_pathc and gl_pathv in
pglob to reflect the paths already scanned. If GLOB_ERR is
not set and either errfunc is a NULL pointer or (*errfunc)
returns 0, the error is ignored.
RETURN VALUES
The following values are returned by glob():
0 Successful completion. The argument pglob->gl_pathc
returns the number of matched path names and the argu-
ment pglob->gl_pathv contains a pointer to a null-
terminated list of matched and sorted path names. How-
ever, if pglob->gl_pathc is 0, the content of
pglob->gl_pathv is undefined.
non-zero
An error has occurred. Non-zero constants are defined
in <glob.h>. The arguments pglob->gl_pathc and
pglob->gl_pathv are still set as defined above.
The globfree() function returns no value.
USAGE
This function is not provided for the purpose of enabling
utilities to perform path name expansion on their arguments,
as this operation is performed by the shell, and utilities
are explicitly not expected to redo this. Instead, it is
provided for applications that need to do path name expan-
sion on strings obtained from other sources, such as a pat-
tern typed by a user or read from a file.
If a utility needs to see if a path name matches a given
pattern, it can use fnmatch(3C).
Note that gl_pathc and gl_pathv have meaning even if glob()
fails. This allows glob() to report partial results in the
event of an error. However, if gl_pathc is 0, gl_pathv is
unspecified even if glob() did not return an error.
The GLOB_NOCHECK option could be used when an application
wants to expand a path name if wildcards are specified, but
wants to treat the pattern as just a string otherwise.
The new path names generated by a subsequent call with
GLOB_APPEND are not sorted together with the previous path
names. This mirrors the way that the shell handles path name
expansion when multiple expansions are done on a command
line.
Applications that need tilde and parameter expansion should
use the wordexp(3C) function.
EXAMPLES
Example 1: Example of glob_doofs function.
One use of the GLOB_DOOFFS flag is by applications that
build an argument list for use with the execv(), execve(),
or execvp() functions (see exec(2)). Suppose, for example,
that an application wants to do the equivalent of:
ls -l *.c
but for some reason:
system("ls -l *.c")
is not acceptable. The application could obtain approxi-
mately the same result using the sequence:
globbuf.gl_offs = 2;
glob ("*.c", GLOB_DOOFFS, NULL, &globbuf);
globbuf.gl_pathv[0] = "ls";
globbuf.gl_pathv[1] = "-l";
execvp ("ls", &globbuf.gl_pathv[0]);
Using the same example:
ls -l *.c *.h
could be approximately simulated using GLOB_APPEND as fol-
lows:
globbuf.gl_offs = 2;
glob ("*.c", GLOB_DOOFFS, NULL, &globbuf);
glob ("*.h", GLOB_DOOFFS|GLOB_APPEND, NULL, &globbuf);
...
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| MT-Level | MT-Safe |
|_____________________________|_____________________________|
SEE ALSO
execv(2), stat(2), fnmatch(3C), opendir(3C), readdir(3C),
wordexp(3C), attributes(5)
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