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
13 glob, globfree — generate pathnames matching a pattern
14
16 #include <glob.h>
17 int glob(const char *restrict pattern, int flags,
19 int(*errfunc)(const char *epath, int eerrno),
20 glob_t *restrict pglob);
21 void globfree(glob_t *pglob);
22
24 The glob() function is a pathname generator that shall implement the
25 rules defined in the Shell and Utilities volume of POSIX.1‐2008, Sec‐
26 tion 2.13, Pattern Matching Notation, with optional support for rule 3
27 in the Shell and Utilities volume of POSIX.1‐2008, Section 2.13.3, Pat‐
28 terns Used for Filename Expansion.
29 The structure type glob_t is defined in <glob.h> and includes at least
31 the following members:
32 ┌──────────────┬──────────────┬─────────────────────────────────────────┐
34 │Member Type │ Member Name │ Description │
35 ├──────────────┼──────────────┼─────────────────────────────────────────┤
36 │size_t │gl_pathc │ Count of paths matched by pattern. │
37 │char ** │gl_pathv │ Pointer to a list of matched pathnames. │
38 │size_t │gl_offs │ Slots to reserve at the beginning of │
39 │ │ │ gl_pathv. │
40 └──────────────┴──────────────┴─────────────────────────────────────────┘
41 The argument pattern is a pointer to a pathname pattern to be expanded.
42 The glob() function shall match all accessible pathnames against this
43 pattern and develop a list of all pathnames that match. In order to
44 have access to a pathname, glob() requires search permission on every
45 component of a path except the last, and read permission on each direc‐
46 tory of any filename component of pattern that contains any of the fol‐
47 lowing special characters: '*', '?', and '['.
48 The glob() function shall store the number of matched pathnames into
50 pglob->gl_pathc and a pointer to a list of pointers to pathnames into
51 pglob->gl_pathv. The pathnames shall be in sort order as defined by the
52 current setting of the LC_COLLATE category; see the Base Definitions
53 volume of POSIX.1‐2008, Section 7.3.2, LC_COLLATE. The first pointer
54 after the last pathname shall be a null pointer. If the pattern does
55 not match any pathnames, the returned number of matched paths is set to
56 0, and the contents of pglob->gl_pathv are implementation-defined.
57 It is the caller's responsibility to create the structure pointed to by
59 pglob. The glob() function shall allocate other space as needed,
60 including the memory pointed to by gl_pathv. The globfree() function
61 shall free any space associated with pglob from a previous call to
62 glob().
63 The flags argument is used to control the behavior of glob(). The
65 value of flags is a bitwise-inclusive OR of zero or more of the follow‐
66 ing constants, which are defined in <glob.h>:
67 GLOB_APPEND Append pathnames generated to the ones from a previous
69 call to glob().
70 GLOB_DOOFFS Make use of pglob->gl_offs. If this flag is set,
72 pglob->gl_offs is used to specify how many null pointers
73 to add to the beginning of pglob->gl_pathv. In other
74 words, pglob->gl_pathv shall point to pglob->gl_offs null
75 pointers, followed by pglob->gl_pathc pathname pointers,
76 followed by a null pointer.
77 GLOB_ERR Cause glob() to return when it encounters a directory
79 that it cannot open or read. Ordinarily, glob() contin‐
80 ues to find matches.
81 GLOB_MARK Each pathname that is a directory that matches pattern
83 shall have a <slash> appended.
84 GLOB_NOCHECK Supports rule 3 in the Shell and Utilities volume of
86 POSIX.1‐2008, Section 2.13.3, Patterns Used for Filename
87 Expansion. If pattern does not match any pathname, then
88 glob() shall return a list consisting of only pattern,
89 and the number of matched pathnames is 1.
90 GLOB_NOESCAPE Disable backslash escaping.
92 GLOB_NOSORT Ordinarily, glob() sorts the matching pathnames according
94 to the current setting of the LC_COLLATE category; see
95 the Base Definitions volume of POSIX.1‐2008, Section
96 7.3.2, LC_COLLATE. When this flag is used, the order of
97 pathnames returned is unspecified.
98 The GLOB_APPEND flag can be used to append a new set of pathnames to
100 those found in a previous call to glob(). The following rules apply to
101 applications when two or more calls to glob() are made with the same
102 value of pglob and without intervening calls to globfree():
103 1. The first such call shall not set GLOB_APPEND. All subsequent calls
105 shall set it.
106 2. All the calls shall set GLOB_DOOFFS, or all shall not set it.
108 3. After the second call, pglob->gl_pathv points to a list containing
110 the following:
111 a. Zero or more null pointers, as specified by GLOB_DOOFFS and
113 pglob->gl_offs.
114 b. Pointers to the pathnames that were in the pglob->gl_pathv list
116 before the call, in the same order as before.
117 c. Pointers to the new pathnames generated by the second call, in
119 the specified order.
120 4. The count returned in pglob->gl_pathc shall be the total number of
122 pathnames from the two calls.
123 5. The application can change any of the fields after a call to
125 glob(). If it does, the application shall reset them to the origi‐
126 nal value before a subsequent call, using the same pglob value, to
127 globfree() or glob() with the GLOB_APPEND flag.
128 If, during the search, a directory is encountered that cannot be opened
130 or read and errfunc is not a null pointer, glob() calls (()*errfunc )
131 with two arguments:
132 1. The epath argument is a pointer to the path that failed.
134 2. The eerrno argument is the value of errno from the failure, as set
136 by opendir(), readdir(), or stat(). (Other values may be used to
137 report other errors not explicitly documented for those functions.)
138 If (()*errfunc ) is called and returns non-zero, or if the GLOB_ERR
140 flag is set in flags, glob() shall stop the scan and return
141 GLOB_ABORTED after setting gl_pathc and gl_pathv in pglob to reflect
142 the paths already scanned. If GLOB_ERR is not set and either errfunc is
143 a null pointer or (()*errfunc ) returns 0, the error shall be ignored.
144 The glob() function shall not fail because of large files.
146
148 Upon successful completion, glob() shall return 0. The argument
149 pglob->gl_pathc shall return the number of matched pathnames and the
150 argument pglob->gl_pathv shall contain a pointer to a null-terminated
151 list of matched and sorted pathnames. However, if pglob->gl_pathc is 0,
152 the content of pglob->gl_pathv is undefined.
153 The globfree() function shall not return a value.
155 If glob() terminates due to an error, it shall return one of the non-
157 zero constants defined in <glob.h>. The arguments pglob->gl_pathc and
158 pglob->gl_pathv are still set as defined above.
159
161 The glob() function shall fail and return the corresponding value if:
162 GLOB_ABORTED The scan was stopped because GLOB_ERR was set or
164 (()*errfunc ) returned non-zero.
165 GLOB_NOMATCH The pattern does not match any existing pathname, and
167 GLOB_NOCHECK was not set in flags.
168 GLOB_NOSPACE An attempt to allocate memory failed.
170 The following sections are informative.
172
174 One use of the GLOB_DOOFFS flag is by applications that build an argu‐
175 ment list for use with execv(), execve(), or execvp(). Suppose, for
176 example, that an application wants to do the equivalent of:
177 ls -l *.c
179 but for some reason:
181 system("ls -l *.c")
183 is not acceptable. The application could obtain approximately the same
185 result using the sequence:
186 globbuf.gl_offs = 2;
188 glob("*.c", GLOB_DOOFFS, NULL, &globbuf);
189 globbuf.gl_pathv[0] = "ls";
190 globbuf.gl_pathv[1] = "-l";
191 execvp("ls", &globbuf.gl_pathv[0]);
192 Using the same example:
194 ls -l *.c *.h
196 could be approximately simulated using GLOB_APPEND as follows:
198 globbuf.gl_offs = 2;
200 glob("*.c", GLOB_DOOFFS, NULL, &globbuf);
201 glob("*.h", GLOB_DOOFFS|GLOB_APPEND, NULL, &globbuf);
202 ...
203
205 This function is not provided for the purpose of enabling utilities to
206 perform pathname expansion on their arguments, as this operation is
207 performed by the shell, and utilities are explicitly not expected to
208 redo this. Instead, it is provided for applications that need to do
209 pathname expansion on strings obtained from other sources, such as a
210 pattern typed by a user or read from a file.
211 If a utility needs to see if a pathname matches a given pattern, it can
213 use fnmatch().
214 Note that gl_pathc and gl_pathv have meaning even if glob() fails. This
216 allows glob() to report partial results in the event of an error. How‐
217 ever, if gl_pathc is 0, gl_pathv is unspecified even if glob() did not
218 return an error.
219 The GLOB_NOCHECK option could be used when an application wants to
221 expand a pathname if wildcards are specified, but wants to treat the
222 pattern as just a string otherwise. The sh utility might use this for
223 option-arguments, for example.
224 The new pathnames generated by a subsequent call with GLOB_APPEND are
226 not sorted together with the previous pathnames. This mirrors the way
227 that the shell handles pathname expansion when multiple expansions are
228 done on a command line.
229 Applications that need tilde and parameter expansion should use word‐
231 exp().
232
234 It was claimed that the GLOB_DOOFFS flag is unnecessary because it
235 could be simulated using:
236 new = (char **)malloc((n + pglob->gl_pathc + 1)
238 * sizeof(char *));
239 (void) memcpy(new+n, pglob->gl_pathv,
240 pglob->gl_pathc * sizeof(char *));
241 (void) memset(new, 0, n * sizeof(char *));
242 free(pglob->gl_pathv);
243 pglob->gl_pathv = new;
244 However, this assumes that the memory pointed to by gl_pathv is a block
246 that was separately created using malloc(). This is not necessarily
247 the case. An application should make no assumptions about how the mem‐
248 ory referenced by fields in pglob was allocated. It might have been
249 obtained from malloc() in a large chunk and then carved up within
250 glob(), or it might have been created using a different memory alloca‐
251 tor. It is not the intent of the standard developers to specify or
252 imply how the memory used by glob() is managed.
253 The GLOB_APPEND flag would be used when an application wants to expand
255 several different patterns into a single list.
256
258 None.
259
261 exec, fdopendir(), fnmatch(), fstatat(), readdir(), Section 2.6, Word
262 Expansions
263 The Base Definitions volume of POSIX.1‐2008, Section 7.3.2, LC_COLLATE,
265 <glob.h>
266
268 Portions of this text are reprinted and reproduced in electronic form
269 from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
270 -- Portable Operating System Interface (POSIX), The Open Group Base
271 Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
272 cal and Electronics Engineers, Inc and The Open Group. (This is
273 POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the
274 event of any discrepancy between this version and the original IEEE and
275 The Open Group Standard, the original IEEE and The Open Group Standard
276 is the referee document. The original Standard can be obtained online
277 at http://www.unix.org/online.html .
278 Any typographical or formatting errors that appear in this page are
280 most likely to have been introduced during the conversion of the source
281 files to man page format. To report such errors, see https://www.ker‐
282 nel.org/doc/man-pages/reporting_bugs.html .
283IEEE/The Open Group 2013 GLOB(3P)