Standards
| Standards / Extensions |
C or C++ |
Dependencies |
|---|
XPG4
XPG4.2
Single UNIX Specification, Version 3
|
both |
|
Format
#define _XOPEN_SOURCE
#include <glob.h>
int glob(const char *__restrict__ pattern, int flags,
int (*errfunc)(const char *epath, int eerrno),
glob_t *__restrict__ pglob);
General description
The glob()
function is a path name generator that implements the rules defined
in topic about pattern matching notation in X/Open CAE Specification, Commands and Utilities,
Issue 4, Version 2,
with optional support for rule 3 in the topic about patterns used
for file name expansion.
The structure
glob_t is
defined in the header <glob.h> and includes at least the following
members:
- gl_pathc
- Count of paths matched by pattern.
- gl_pathv
- Pointer to a list of matched file names.
- gl_offs
- Slots to reserve at the beginning of gl_pathv.
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
file name component of
pattern that contains
any of the following special characters:
* ? [
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, see X/Open CAE Specification, System Interface Definitions,
Issue 4, Version 2 topic,
LC_COLLATE. 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
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 previous 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() continues to find matches.
- GLOB_MARK
- Each path name
that is a directory that matches pattern has
a slash appended.
- GLOB_NOCHECK
- Support rule
3 in the XCU specification, topic, Patterns Used for Filename Expansion.
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, see the XBD specification, topic,
LC_COLLATE. 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 following rules apply when two or more calls to glob() are made
with the same value of
pglob and without
intervening calls to globfree():
- The first such call must not set GLOB_APPEND. All subsequent calls
must set it.
- All calls must set GLOB_DOOFFS, or all must not set it.
- After the second call, pglob->gl_pathv points
to a list containing the following:
- Zero or more NULL pointers, as specified by GLOB_DOOFFS and pglob->gl_offs.
- Pointers to the path names that were in the pglob->gl_pathv list
before the call, in the same order as before.
- Pointers to the new path names generated by the second call, in
the specified order.
- The count returned in pglob->gl_pathc will
be the total number of path names from the two calls.
- 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.
If, during the search, a directory is encountered that
cannot be opened or read and
errfunc is
not a NULL pointer, glob() calls (*
errfunc())
with two arguments:
- The epath argument is a pointer to the
path that failed.
- The eerrno argument is the value of
errno from the failure, as set by opendir(), readdir() or stat().
(Other values may be used to report other errors not explicitly documented
for those functions.)
Returned value
If successful, glob() returns
0. The argument pglob->gl_pathc returns
the number of matched path names and the argument pglob->gl_pathv contains
a pointer to a NULL-terminated list of matched and sorted path names.
However, if pglob->gl_pathc is 0, the
content of pglob->gl_pathv is undefined.
If
glob() terminates due to an error, it returns one of the following
nonzero constants defined in <glob.h> as error return values
for glob():
- GLOB_ABORTED
- The scan
was stopped because GLOB_ERR was set or (*errfunc())
returned nonzero.
- GLOB_NOMATCH
- The pattern
does not match any existing path name, and GLOB_NOCHECK was set in flags.
- GLOB_NOSPACE
- An attempt
to allocate memory failed.
If (*errfunc()) is
called and returns nonzero, 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.