1GLOB(3P) POSIX Programmer's Manual GLOB(3P)
2
6 This manual page is part of the POSIX Programmer's Manual. The Linux
7 implementation of this interface may differ (consult the corresponding
8 Linux manual page for details of Linux behavior), or the interface may
9 not be implemented on Linux.
10
12 glob, globfree - generate pathnames matching a pattern
13
15 #include <glob.h>
16 int glob(const char *restrict pattern, int flags,
18 int(*errfunc)(const char *epath, int eerrno),
19 glob_t *restrict pglob);
20 void globfree(glob_t *pglob);
21
24 The glob() function is a pathname generator that shall implement the
25 rules defined in the Shell and Utilities volume of
26 IEEE Std 1003.1-2001, Section 2.13, Pattern Matching Notation, with
27 optional support for rule 3 in the Shell and Utilities volume of
28 IEEE Std 1003.1-2001, Section 2.13.3, Patterns Used for Filename Expan‐
29 sion.
30 The structure type glob_t is defined in <glob.h> and includes at least
32 the following members:
33 Member Type Member Name Description
35 size_t gl_pathc Count of paths matched by pattern.
36 char ** gl_pathv Pointer to a list of matched pathnames.
37 size_t gl_offs Slots to reserve at the beginning of gl_pathv.
38 The argument pattern is a pointer to a pathname pattern to be expanded.
40 The glob() function shall match all accessible pathnames against this
41 pattern and develop a list of all pathnames that match. In order to
42 have access to a pathname, glob() requires search permission on every
43 component of a path except the last, and read permission on each direc‐
44 tory of any filename component of pattern that contains any of the fol‐
45 lowing special characters: '*', '?', and '[' .
46 The glob() function shall store the number of matched pathnames into
48 pglob->gl_pathc and a pointer to a list of pointers to pathnames into
49 pglob->gl_pathv. The pathnames shall be in sort order as defined by the
50 current setting of the LC_COLLATE category; see the Base Definitions
51 volume of IEEE Std 1003.1-2001, Section 7.3.2, LC_COLLATE. The first
52 pointer after the last pathname shall be a null pointer. If the pattern
53 does not match any pathnames, the returned number of matched paths is
54 set to 0, and the contents of pglob->gl_pathv are implementation-
55 defined.
56 It is the caller's responsibility to create the structure pointed to by
58 pglob. The glob() function shall allocate other space as needed,
59 including the memory pointed to by gl_pathv. The globfree() function
60 shall free any space associated with pglob from a previous call to
61 glob().
62 The flags argument is used to control the behavior of glob(). The
64 value of flags is a bitwise-inclusive OR of zero or more of the follow‐
65 ing constants, which are defined in <glob.h>:
66 GLOB_APPEND
68 Append pathnames generated to the ones from a previous call to
69 glob().
70 GLOB_DOOFFS
72 Make use of pglob->gl_offs. If this flag is set, pglob->gl_offs
73 is used to specify how many null pointers to add to the begin‐
74 ning of pglob->gl_pathv. In other words, pglob->gl_pathv shall
75 point to pglob->gl_offs null pointers, followed by
76 pglob->gl_pathc pathname pointers, followed by a null pointer.
77 GLOB_ERR
79 Cause glob() to return when it encounters a directory that it
80 cannot open or read. Ordinarily, glob() continues to find
81 matches.
82 GLOB_MARK
84 Each pathname that is a directory that matches pattern shall
85 have a slash appended.
86 GLOB_NOCHECK
88 Supports rule 3 in the Shell and Utilities volume of
89 IEEE Std 1003.1-2001, Section 2.13.3, Patterns Used for Filename
90 Expansion. If pattern does not match any pathname, then glob()
91 shall return a list consisting of only pattern, and the number
92 of matched pathnames is 1.
93 GLOB_NOESCAPE
95 Disable backslash escaping.
96 GLOB_NOSORT
98 Ordinarily, glob() sorts the matching pathnames according to the
99 current setting of the LC_COLLATE category; see the Base Defini‐
100 tions volume of IEEE Std 1003.1-2001, Section 7.3.2, LC_COLLATE.
101 When this flag is used, the order of pathnames returned is
102 unspecified.
103 The GLOB_APPEND flag can be used to append a new set of pathnames to
106 those found in a previous call to glob(). The following rules apply to
107 applications when two or more calls to glob() are made with the same
108 value of pglob and without intervening calls to globfree():
109 1. The first such call shall not set GLOB_APPEND. All subsequent calls
111 shall set it.
112 2. All the calls shall set GLOB_DOOFFS, or all shall not set it.
114 3. After the second call, pglob->gl_pathv points to a list containing
116 the following:
117 a. Zero or more null pointers, as specified by GLOB_DOOFFS and
119 pglob->gl_offs.
120 b. Pointers to the pathnames that were in the pglob->gl_pathv list
122 before the call, in the same order as before.
123 c. Pointers to the new pathnames generated by the second call, in
125 the specified order.
126 4. The count returned in pglob->gl_pathc shall be the total number of
128 pathnames from the two calls.
129 5. The application can change any of the fields after a call to
131 glob(). If it does, the application shall reset them to the origi‐
132 nal value before a subsequent call, using the same pglob value, to
133 globfree() or glob() with the GLOB_APPEND flag.
134 If, during the search, a directory is encountered that cannot be opened
136 or read and errfunc is not a null pointer, glob() calls (*errfunc())
137 with two arguments:
138 1. The epath argument is a pointer to the path that failed.
140 2. The eerrno argument is the value of errno from the failure, as set
142 by opendir(), readdir(), or stat(). (Other values may be used to
143 report other errors not explicitly documented for those functions.)
144 If (*errfunc()) is called and returns non-zero, or if the GLOB_ERR flag
146 is set in flags, glob() shall stop the scan and return GLOB_ABORTED
147 after setting gl_pathc and gl_pathv in pglob to reflect the paths
148 already scanned. If GLOB_ERR is not set and either errfunc is a null
149 pointer or (*errfunc()) returns 0, the error shall be ignored.
150 The glob() function shall not fail because of large files.
152
154 Upon successful completion, glob() shall return 0. The argument
155 pglob->gl_pathc shall return the number of matched pathnames and the
156 argument pglob->gl_pathv shall contain a pointer to a null-terminated
157 list of matched and sorted pathnames. However, if pglob->gl_pathc is 0,
158 the content of pglob->gl_pathv is undefined.
159 The globfree() function shall not return a value.
161 If glob() terminates due to an error, it shall return one of the non-
163 zero constants defined in <glob.h>. The arguments pglob->gl_pathc and
164 pglob->gl_pathv are still set as defined above.
165
167 The glob() function shall fail and return the corresponding value if:
168 GLOB_ABORTED
170 The scan was stopped because GLOB_ERR was set or (*errfunc())
171 returned non-zero.
172 GLOB_NOMATCH
174 The pattern does not match any existing pathname, and
175 GLOB_NOCHECK was not set in flags.
176 GLOB_NOSPACE
178 An attempt to allocate memory failed.
179 The following sections are informative.
182
184 One use of the GLOB_DOOFFS flag is by applications that build an argu‐
185 ment list for use with execv(), execve(), or execvp(). Suppose, for
186 example, that an application wants to do the equivalent of:
187 ls -l *.c
190 but for some reason:
192 system("ls -l *.c")
195 is not acceptable. The application could obtain approximately the same
197 result using the sequence:
198 globbuf.gl_offs = 2;
201 glob("*.c", GLOB_DOOFFS, NULL, &globbuf);
202 globbuf.gl_pathv[0] = "ls";
203 globbuf.gl_pathv[1] = "-l";
204 execvp("ls", &globbuf.gl_pathv[0]);
205 Using the same example:
207 ls -l *.c *.h
210 could be approximately simulated using GLOB_APPEND as follows:
212 globbuf.gl_offs = 2;
215 glob("*.c", GLOB_DOOFFS, NULL, &globbuf);
216 glob("*.h", GLOB_DOOFFS|GLOB_APPEND, NULL, &globbuf);
217 ...
218
220 This function is not provided for the purpose of enabling utilities to
221 perform pathname expansion on their arguments, as this operation is
222 performed by the shell, and utilities are explicitly not expected to
223 redo this. Instead, it is provided for applications that need to do
224 pathname expansion on strings obtained from other sources, such as a
225 pattern typed by a user or read from a file.
226 If a utility needs to see if a pathname matches a given pattern, it can
228 use fnmatch().
229 Note that gl_pathc and gl_pathv have meaning even if glob() fails. This
231 allows glob() to report partial results in the event of an error. How‐
232 ever, if gl_pathc is 0, gl_pathv is unspecified even if glob() did not
233 return an error.
234 The GLOB_NOCHECK option could be used when an application wants to
236 expand a pathname if wildcards are specified, but wants to treat the
237 pattern as just a string otherwise. The sh utility might use this for
238 option-arguments, for example.
239 The new pathnames generated by a subsequent call with GLOB_APPEND are
241 not sorted together with the previous pathnames. This mirrors the way
242 that the shell handles pathname expansion when multiple expansions are
243 done on a command line.
244 Applications that need tilde and parameter expansion should use word‐
246 exp().
247
249 It was claimed that the GLOB_DOOFFS flag is unnecessary because it
250 could be simulated using:
251 new = (char **)malloc((n + pglob->gl_pathc + 1)
254 * sizeof(char *));
255 (void) memcpy(new+n, pglob->gl_pathv,
256 pglob->gl_pathc * sizeof(char *));
257 (void) memset(new, 0, n * sizeof(char *));
258 free(pglob->gl_pathv);
259 pglob->gl_pathv = new;
260 However, this assumes that the memory pointed to by gl_pathv is a block
262 that was separately created using malloc(). This is not necessarily the
263 case. An application should make no assumptions about how the memory
264 referenced by fields in pglob was allocated. It might have been
265 obtained from malloc() in a large chunk and then carved up within
266 glob(), or it might have been created using a different memory alloca‐
267 tor. It is not the intent of the standard developers to specify or
268 imply how the memory used by glob() is managed.
269 The GLOB_APPEND flag would be used when an application wants to expand
271 several different patterns into a single list.
272
274 None.
275
277 exec(), fnmatch(), opendir(), readdir(), stat(), wordexp(), the Base
278 Definitions volume of IEEE Std 1003.1-2001, <glob.h>, the Shell and
279 Utilities volume of IEEE Std 1003.1-2001
280
282 Portions of this text are reprinted and reproduced in electronic form
283 from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
284 -- Portable Operating System Interface (POSIX), The Open Group Base
285 Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
286 Electrical and Electronics Engineers, Inc and The Open Group. In the
287 event of any discrepancy between this version and the original IEEE and
288 The Open Group Standard, the original IEEE and The Open Group Standard
289 is the referee document. The original Standard can be obtained online
290 at http://www.opengroup.org/unix/online.html .
291IEEE/The Open Group 2003 GLOB(3P)