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
23 The glob() function is a pathname generator that shall implement the
24 rules defined in the Shell and Utilities volume of POSIX.1‐2017, Sec‐
25 tion 2.13, Pattern Matching Notation, with optional support for rule 3
26 in the Shell and Utilities volume of POSIX.1‐2017, Section 2.13.3, Pat‐
27 terns Used for Filename Expansion.
28 The structure type glob_t is defined in <glob.h> and includes at least
30 the following members:
31 ┌──────────────┬──────────────┬─────────────────────────────────────────┐
33 │Member Type │ Member Name │ Description │
34 ├──────────────┼──────────────┼─────────────────────────────────────────┤
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 │
38 │ │ │ gl_pathv. │
39 └──────────────┴──────────────┴─────────────────────────────────────────┘
40 The argument pattern is a pointer to a pathname pattern to be expanded.
41 The glob() function shall match all accessible pathnames against this
42 pattern and develop a list of all pathnames that match. In order to
43 have access to a pathname, glob() requires search permission on every
44 component of a path except the last, and read permission on each direc‐
45 tory of any filename component of pattern that contains any of the fol‐
46 lowing special characters: '*', '?', and '['.
47 The glob() function shall store the number of matched pathnames into
49 pglob->gl_pathc and a pointer to a list of pointers to pathnames into
50 pglob->gl_pathv. The pathnames shall be in sort order as defined by the
51 current setting of the LC_COLLATE category; see the Base Definitions
52 volume of POSIX.1‐2017, Section 7.3.2, LC_COLLATE. The first pointer
53 after the last pathname shall be a null pointer. If the pattern does
54 not match any pathnames, the returned number of matched paths is set to
55 0, and the contents of pglob->gl_pathv are implementation-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 Append pathnames generated to the ones from a previous
68 call to glob().
69 GLOB_DOOFFS Make use of pglob->gl_offs. If this flag is set,
71 pglob->gl_offs is used to specify how many null pointers
72 to add to the beginning of pglob->gl_pathv. In other
73 words, pglob->gl_pathv shall point to pglob->gl_offs null
74 pointers, followed by pglob->gl_pathc pathname pointers,
75 followed by a null pointer.
76 GLOB_ERR Cause glob() to return when it encounters a directory
78 that it cannot open or read. Ordinarily, glob() contin‐
79 ues to find matches.
80 GLOB_MARK Each pathname that is a directory that matches pattern
82 shall have a <slash> appended.
83 GLOB_NOCHECK Supports rule 3 in the Shell and Utilities volume of
85 POSIX.1‐2017, Section 2.13.3, Patterns Used for Filename
86 Expansion. If pattern does not match any pathname, then
87 glob() shall return a list consisting of only pattern,
88 and the number of matched pathnames is 1.
89 GLOB_NOESCAPE Disable backslash escaping.
91 GLOB_NOSORT Ordinarily, glob() sorts the matching pathnames according
93 to the current setting of the LC_COLLATE category; see
94 the Base Definitions volume of POSIX.1‐2017, Section
95 7.3.2, LC_COLLATE. When this flag is used, the order of
96 pathnames returned is unspecified.
97 The GLOB_APPEND flag can be used to append a new set of pathnames to
99 those found in a previous call to glob(). The following rules apply to
100 applications when two or more calls to glob() are made with the same
101 value of pglob and without intervening calls to globfree():
102 1. The first such call shall not set GLOB_APPEND. All subsequent calls
104 shall set it.
105 2. All the calls shall set GLOB_DOOFFS, or all shall not set it.
107 3. After the second call, pglob->gl_pathv points to a list containing
109 the following:
110 a. Zero or more null pointers, as specified by GLOB_DOOFFS and
112 pglob->gl_offs.
113 b. Pointers to the pathnames that were in the pglob->gl_pathv list
115 before the call, in the same order as before.
116 c. Pointers to the new pathnames generated by the second call, in
118 the specified order.
119 4. The count returned in pglob->gl_pathc shall be the total number of
121 pathnames from the two calls.
122 5. The application can change any of the fields after a call to
124 glob(). If it does, the application shall reset them to the origi‐
125 nal value before a subsequent call, using the same pglob value, to
126 globfree() or glob() with the GLOB_APPEND flag.
127 If, during the search, a directory is encountered that cannot be opened
129 or read and errfunc is not a null pointer, glob() calls (()*errfunc )
130 with two arguments:
131 1. The epath argument is a pointer to the path that failed.
133 2. The eerrno argument is the value of errno from the failure, as set
135 by opendir(), readdir(), or stat(). (Other values may be used to
136 report other errors not explicitly documented for those functions.)
137 If (()*errfunc ) is called and returns non-zero, or if the GLOB_ERR
139 flag is set in flags, glob() shall stop the scan and return
140 GLOB_ABORTED after setting gl_pathc and gl_pathv in pglob to reflect
141 the paths already scanned. If GLOB_ERR is not set and either errfunc is
142 a null pointer or (()*errfunc ) returns 0, the error shall be ignored.
143 The glob() function shall not fail because of large files.
145
147 Upon successful completion, glob() shall return 0. The argument
148 pglob->gl_pathc shall return the number of matched pathnames and the
149 argument pglob->gl_pathv shall contain a pointer to a null-terminated
150 list of matched and sorted pathnames. However, if pglob->gl_pathc is 0,
151 the content of pglob->gl_pathv is undefined.
152 The globfree() function shall not return a value.
154 If glob() terminates due to an error, it shall return one of the non-
156 zero constants defined in <glob.h>. The arguments pglob->gl_pathc and
157 pglob->gl_pathv are still set as defined above.
158
160 The glob() function shall fail and return the corresponding value if:
161 GLOB_ABORTED The scan was stopped because GLOB_ERR was set or
163 (()*errfunc ) returned non-zero.
164 GLOB_NOMATCH The pattern does not match any existing pathname, and
166 GLOB_NOCHECK was not set in flags.
167 GLOB_NOSPACE An attempt to allocate memory failed.
169 The following sections are informative.
171
173 One use of the GLOB_DOOFFS flag is by applications that build an argu‐
174 ment list for use with execv(), execve(), or execvp(). Suppose, for
175 example, that an application wants to do the equivalent of:
176 ls -l *.c
179 but for some reason:
181 system("ls -l *.c")
184 is not acceptable. The application could obtain approximately the same
186 result using the sequence:
187 globbuf.gl_offs = 2;
190 glob("*.c", GLOB_DOOFFS, NULL, &globbuf);
191 globbuf.gl_pathv[0] = "ls";
192 globbuf.gl_pathv[1] = "-l";
193 execvp("ls", &globbuf.gl_pathv[0]);
194 Using the same example:
196 ls -l *.c *.h
199 could be approximately simulated using GLOB_APPEND as follows:
201 globbuf.gl_offs = 2;
204 glob("*.c", GLOB_DOOFFS, NULL, &globbuf);
205 glob("*.h", GLOB_DOOFFS|GLOB_APPEND, NULL, &globbuf);
206 ...
207
209 This function is not provided for the purpose of enabling utilities to
210 perform pathname expansion on their arguments, as this operation is
211 performed by the shell, and utilities are explicitly not expected to
212 redo this. Instead, it is provided for applications that need to do
213 pathname expansion on strings obtained from other sources, such as a
214 pattern typed by a user or read from a file.
215 If a utility needs to see if a pathname matches a given pattern, it can
217 use fnmatch().
218 Note that gl_pathc and gl_pathv have meaning even if glob() fails. This
220 allows glob() to report partial results in the event of an error. How‐
221 ever, if gl_pathc is 0, gl_pathv is unspecified even if glob() did not
222 return an error.
223 The GLOB_NOCHECK option could be used when an application wants to
225 expand a pathname if wildcards are specified, but wants to treat the
226 pattern as just a string otherwise. The sh utility might use this for
227 option-arguments, for example.
228 The new pathnames generated by a subsequent call with GLOB_APPEND are
230 not sorted together with the previous pathnames. This mirrors the way
231 that the shell handles pathname expansion when multiple expansions are
232 done on a command line.
233 Applications that need tilde and parameter expansion should use word‐
235 exp().
236
238 It was claimed that the GLOB_DOOFFS flag is unnecessary because it
239 could be simulated using:
240 new = (char **)malloc((n + pglob->gl_pathc + 1)
243 * sizeof(char *));
244 (void) memcpy(new+n, pglob->gl_pathv,
245 pglob->gl_pathc * sizeof(char *));
246 (void) memset(new, 0, n * sizeof(char *));
247 free(pglob->gl_pathv);
248 pglob->gl_pathv = new;
249 However, this assumes that the memory pointed to by gl_pathv is a block
251 that was separately created using malloc(). This is not necessarily
252 the case. An application should make no assumptions about how the mem‐
253 ory referenced by fields in pglob was allocated. It might have been
254 obtained from malloc() in a large chunk and then carved up within
255 glob(), or it might have been created using a different memory alloca‐
256 tor. It is not the intent of the standard developers to specify or
257 imply how the memory used by glob() is managed.
258 The GLOB_APPEND flag would be used when an application wants to expand
260 several different patterns into a single list.
261
263 None.
264
266 exec, fdopendir(), fnmatch(), fstatat(), readdir(), Section 2.6, Word
267 Expansions
268 The Base Definitions volume of POSIX.1‐2017, Section 7.3.2, LC_COLLATE,
270 <glob.h>
271
273 Portions of this text are reprinted and reproduced in electronic form
274 from IEEE Std 1003.1-2017, Standard for Information Technology -- Por‐
275 table Operating System Interface (POSIX), The Open Group Base Specifi‐
276 cations Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of
277 Electrical and Electronics Engineers, Inc and The Open Group. In the
278 event of any discrepancy between this version and the original IEEE and
279 The Open Group Standard, the original IEEE and The Open Group Standard
280 is the referee document. The original Standard can be obtained online
281 at http://www.opengroup.org/unix/online.html .
282 Any typographical or formatting errors that appear in this page are
284 most likely to have been introduced during the conversion of the source
285 files to man page format. To report such errors, see https://www.ker‐
286 nel.org/doc/man-pages/reporting_bugs.html .
287IEEE/The Open Group 2017 GLOB(3P)