1GLOB(P) POSIX Programmer's Manual GLOB(P)
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6 glob, globfree - generate pathnames matching a pattern
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9 #include <glob.h>
10 int glob(const char *restrict pattern, int flags,
12 int(*errfunc)(const char *epath, int eerrno),
13 glob_t *restrict pglob);
14 void globfree(glob_t *pglob);
15
18 The glob() function is a pathname generator that shall implement the
19 rules defined in the Shell and Utilities volume of
20 IEEE Std 1003.1-2001, Section 2.13, Pattern Matching Notation, with
21 optional support for rule 3 in the Shell and Utilities volume of
22 IEEE Std 1003.1-2001, Section 2.13.3, Patterns Used for Filename Expan‐
23 sion.
24 The structure type glob_t is defined in <glob.h> and includes at least
26 the following members:
27 Member Type Member Name Description
29 size_t gl_pathc Count of paths matched by pattern.
30 char ** gl_pathv Pointer to a list of matched pathnames.
31 size_t gl_offs Slots to reserve at the beginning of gl_pathv.
32 The argument pattern is a pointer to a pathname pattern to be expanded.
34 The glob() function shall match all accessible pathnames against this
35 pattern and develop a list of all pathnames that match. In order to
36 have access to a pathname, glob() requires search permission on every
37 component of a path except the last, and read permission on each direc‐
38 tory of any filename component of pattern that contains any of the fol‐
39 lowing special characters: '*' , '?' , and '[' .
40 The glob() function shall store the number of matched pathnames into
42 pglob->gl_pathc and a pointer to a list of pointers to pathnames into
43 pglob->gl_pathv. The pathnames shall be in sort order as defined by the
44 current setting of the LC_COLLATE category; see the Base Definitions
45 volume of IEEE Std 1003.1-2001, Section 7.3.2, LC_COLLATE. The first
46 pointer after the last pathname shall be a null pointer. If the pattern
47 does not match any pathnames, the returned number of matched paths is
48 set to 0, and the contents of pglob->gl_pathv are implementation-
49 defined.
50 It is the caller's responsibility to create the structure pointed to by
52 pglob. The glob() function shall allocate other space as needed,
53 including the memory pointed to by gl_pathv. The globfree() function
54 shall free any space associated with pglob from a previous call to
55 glob().
56 The flags argument is used to control the behavior of glob(). The
58 value of flags is a bitwise-inclusive OR of zero or more of the follow‐
59 ing constants, which are defined in <glob.h>:
60 GLOB_APPEND
62 Append pathnames generated to the ones from a previous call to
63 glob().
64 GLOB_DOOFFS
66 Make use of pglob->gl_offs. If this flag is set, pglob->gl_offs
67 is used to specify how many null pointers to add to the begin‐
68 ning of pglob->gl_pathv. In other words, pglob->gl_pathv shall
69 point to pglob->gl_offs null pointers, followed by
70 pglob->gl_pathc pathname pointers, followed by a null pointer.
71 GLOB_ERR
73 Cause glob() to return when it encounters a directory that it
74 cannot open or read. Ordinarily, glob() continues to find
75 matches.
76 GLOB_MARK
78 Each pathname that is a directory that matches pattern shall
79 have a slash appended.
80 GLOB_NOCHECK
82 Supports rule 3 in the Shell and Utilities volume of
83 IEEE Std 1003.1-2001, Section 2.13.3, Patterns Used for Filename
84 Expansion. If pattern does not match any pathname, then glob()
85 shall return a list consisting of only pattern, and the number
86 of matched pathnames is 1.
87 GLOB_NOESCAPE
89 Disable backslash escaping.
90 GLOB_NOSORT
92 Ordinarily, glob() sorts the matching pathnames according to the
93 current setting of the LC_COLLATE category; see the Base Defini‐
94 tions volume of IEEE Std 1003.1-2001, Section 7.3.2, LC_COLLATE.
95 When this flag is used, the order of pathnames returned is
96 unspecified.
97 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 flag
140 is set in flags, glob() shall stop the scan and return GLOB_ABORTED
141 after setting gl_pathc and gl_pathv in pglob to reflect the paths
142 already scanned. If GLOB_ERR is not set and either errfunc is a null
143 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
164 The scan was stopped because GLOB_ERR was set or (*errfunc())
165 returned non-zero.
166 GLOB_NOMATCH
168 The pattern does not match any existing pathname, and
169 GLOB_NOCHECK was not set in flags.
170 GLOB_NOSPACE
172 An attempt to allocate memory failed.
173 The following sections are informative.
176
178 One use of the GLOB_DOOFFS flag is by applications that build an argu‐
179 ment list for use with execv(), execve(), or execvp(). Suppose, for
180 example, that an application wants to do the equivalent of:
181 ls -l *.c
184 but for some reason:
186 system("ls -l *.c")
189 is not acceptable. The application could obtain approximately the same
191 result using the sequence:
192 globbuf.gl_offs = 2;
195 glob("*.c", GLOB_DOOFFS, NULL, &globbuf);
196 globbuf.gl_pathv[0] = "ls";
197 globbuf.gl_pathv[1] = "-l";
198 execvp("ls", &globbuf.gl_pathv[0]);
199 Using the same example:
201 ls -l *.c *.h
204 could be approximately simulated using GLOB_APPEND as follows:
206 globbuf.gl_offs = 2;
209 glob("*.c", GLOB_DOOFFS, NULL, &globbuf);
210 glob("*.h", GLOB_DOOFFS|GLOB_APPEND, NULL, &globbuf);
211 ...
212
214 This function is not provided for the purpose of enabling utilities to
215 perform pathname expansion on their arguments, as this operation is
216 performed by the shell, and utilities are explicitly not expected to
217 redo this. Instead, it is provided for applications that need to do
218 pathname expansion on strings obtained from other sources, such as a
219 pattern typed by a user or read from a file.
220 If a utility needs to see if a pathname matches a given pattern, it can
222 use fnmatch().
223 Note that gl_pathc and gl_pathv have meaning even if glob() fails. This
225 allows glob() to report partial results in the event of an error. How‐
226 ever, if gl_pathc is 0, gl_pathv is unspecified even if glob() did not
227 return an error.
228 The GLOB_NOCHECK option could be used when an application wants to
230 expand a pathname if wildcards are specified, but wants to treat the
231 pattern as just a string otherwise. The sh utility might use this for
232 option-arguments, for example.
233 The new pathnames generated by a subsequent call with GLOB_APPEND are
235 not sorted together with the previous pathnames. This mirrors the way
236 that the shell handles pathname expansion when multiple expansions are
237 done on a command line.
238 Applications that need tilde and parameter expansion should use word‐
240 exp().
241
243 It was claimed that the GLOB_DOOFFS flag is unnecessary because it
244 could be simulated using:
245 new = (char **)malloc((n + pglob->gl_pathc + 1)
248 * sizeof(char *));
249 (void) memcpy(new+n, pglob->gl_pathv,
250 pglob->gl_pathc * sizeof(char *));
251 (void) memset(new, 0, n * sizeof(char *));
252 free(pglob->gl_pathv);
253 pglob->gl_pathv = new;
254 However, this assumes that the memory pointed to by gl_pathv is a block
256 that was separately created using malloc(). This is not necessarily the
257 case. An application should make no assumptions about how the memory
258 referenced by fields in pglob was allocated. It might have been
259 obtained from malloc() in a large chunk and then carved up within
260 glob(), or it might have been created using a different memory alloca‐
261 tor. It is not the intent of the standard developers to specify or
262 imply how the memory used by glob() is managed.
263 The GLOB_APPEND flag would be used when an application wants to expand
265 several different patterns into a single list.
266
268 None.
269
271 exec() , fnmatch() , opendir() , readdir() , stat() , wordexp() , the
272 Base Definitions volume of IEEE Std 1003.1-2001, <glob.h>, the Shell
273 and Utilities volume of IEEE Std 1003.1-2001
274
276 Portions of this text are reprinted and reproduced in electronic form
277 from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
278 -- Portable Operating System Interface (POSIX), The Open Group Base
279 Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
280 Electrical and Electronics Engineers, Inc and The Open Group. In the
281 event of any discrepancy between this version and the original IEEE and
282 The Open Group Standard, the original IEEE and The Open Group Standard
283 is the referee document. The original Standard can be obtained online
284 at http://www.opengroup.org/unix/online.html .
285IEEE/The Open Group 2003 GLOB(P)