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GLOB(3) Linux Programmer's Manual GLOB(3)
NAME
glob, globfree - find pathnames matching a pattern, free memory from glob()
SYNOPSIS
#include <glob.h>
int glob(const char *restrict pattern, int flags,
int (*errfunc)(const char *epath, int eerrno),
glob_t *restrict pglob);
void globfree(glob_t *pglob);
DESCRIPTION
The glob() function searches for all the pathnames matching pattern according to the rules used by the shell (see glob(7)). No tilde expansion or parameter sub‐
stitution is done; if you want these, use wordexp(3).
The globfree() function frees the dynamically allocated storage from an earlier call to glob().
The results of a glob() call are stored in the structure pointed to by pglob. This structure is of type glob_t (declared in <glob.h>) and includes the following
elements defined by POSIX.2 (more may be present as an extension):
typedef struct {
size_t gl_pathc; /* Count of paths matched so far */
char **gl_pathv; /* List of matched pathnames. */
size_t gl_offs; /* Slots to reserve in gl_pathv. */
} glob_t;
Results are stored in dynamically allocated storage.
The argument flags is made up of the bitwise OR of zero or more the following symbolic constants, which modify the behavior of glob():
GLOB_ERR
Return upon a read error (because a directory does not have read permission, for example). By default, glob() attempts carry on despite errors, reading
all of the directories that it can.
GLOB_MARK
Append a slash to each path which corresponds to a directory.
GLOB_NOSORT
Don't sort the returned pathnames. The only reason to do this is to save processing time. By default, the returned pathnames are sorted.
GLOB_DOOFFS
Reserve pglob->gl_offs slots at the beginning of the list of strings in pglob->pathv. The reserved slots contain null pointers.
GLOB_NOCHECK
If no pattern matches, return the original pattern. By default, glob() returns GLOB_NOMATCH if there are no matches.
GLOB_APPEND
Append the results of this call to the vector of results returned by a previous call to glob(). Do not set this flag on the first invocation of glob().
GLOB_NOESCAPE
Don't allow backslash ('\') to be used as an escape character. Normally, a backslash can be used to quote the following character, providing a mechanism
to turn off the special meaning metacharacters.
flags may also include any of the following, which are GNU extensions and not defined by POSIX.2:
GLOB_PERIOD
Allow a leading period to be matched by metacharacters. By default, metacharacters can't match a leading period.
GLOB_ALTDIRFUNC
Use alternative functions pglob->gl_closedir, pglob->gl_readdir, pglob->gl_opendir, pglob->gl_lstat, and pglob->gl_stat for filesystem access instead of
the normal library functions.
GLOB_BRACE
Expand csh(1) style brace expressions of the form {a,b}. Brace expressions can be nested. Thus, for example, specifying the pattern
"{foo/{,cat,dog},bar}" would return the same results as four separate glob() calls using the strings: "foo/", "foo/cat", "foo/dog", and "bar".
GLOB_NOMAGIC
If the pattern contains no metacharacters, then it should be returned as the sole matching word, even if there is no file with that name.
GLOB_TILDE
Carry out tilde expansion. If a tilde ('~') is the only character in the pattern, or an initial tilde is followed immediately by a slash ('/'), then the
home directory of the caller is substituted for the tilde. If an initial tilde is followed by a username (e.g., "~andrea/bin"), then the tilde and user‐
name are substituted by the home directory of that user. If the username is invalid, or the home directory cannot be determined, then no substitution is
performed.
GLOB_TILDE_CHECK
This provides behavior similar to that of GLOB_TILDE. The difference is that if the username is invalid, or the home directory cannot be determined, then
instead of using the pattern itself as the name, glob() returns GLOB_NOMATCH to indicate an error.
GLOB_ONLYDIR
This is a hint to glob() that the caller is interested only in directories that match the pattern. If the implementation can easily determine file-type
information, then nondirectory files are not returned to the caller. However, the caller must still check that returned files are directories. (The pur‐
pose of this flag is merely to optimize performance when the caller is interested only in directories.)
If errfunc is not NULL, it will be called in case of an error with the arguments epath, a pointer to the path which failed, and eerrno, the value of errno as re‐
turned from one of the calls to opendir(3), readdir(3), or stat(2). If errfunc returns nonzero, or if GLOB_ERR is set, glob() will terminate after the call to
errfunc.
Upon successful return, pglob->gl_pathc contains the number of matched pathnames and pglob->gl_pathv contains a pointer to the list of pointers to matched path‐
names. The list of pointers is terminated by a null pointer.
It is possible to call glob() several times. In that case, the GLOB_APPEND flag has to be set in flags on the second and later invocations.
As a GNU extension, pglob->gl_flags is set to the flags specified, ored with GLOB_MAGCHAR if any metacharacters were found.
RETURN VALUE
On successful completion, glob() returns zero. Other possible returns are:
GLOB_NOSPACE
for running out of memory,
GLOB_ABORTED
for a read error, and
GLOB_NOMATCH
for no found matches.
ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7).
┌───────────┬───────────────┬────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
│Interface │ Attribute │ Value │
├───────────┼───────────────┼────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┤
│glob() │ Thread safety │ MT-Unsafe race:utent env sig:ALRM timer locale │
├───────────┼───────────────┼────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┤
│globfree() │ Thread safety │ MT-Safe │
└───────────┴───────────────┴────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
In the above table, utent in race:utent signifies that if any of the functions setutent(3), getutent(3), or endutent(3) are used in parallel in different threads
of a program, then data races could occur. glob() calls those functions, so we use race:utent to remind users.
CONFORMING TO
POSIX.1-2001, POSIX.1-2008, POSIX.2.
NOTES
The structure elements gl_pathc and gl_offs are declared as size_t in glibc 2.1, as they should be according to POSIX.2, but are declared as int in glibc 2.0.
BUGS
The glob() function may fail due to failure of underlying function calls, such as malloc(3) or opendir(3). These will store their error code in errno.
EXAMPLES
One example of use is the following code, which simulates typing
ls -l *.c ../*.c
in the shell:
glob_t globbuf;
globbuf.gl_offs = 2;
glob("*.c", GLOB_DOOFFS, NULL, &globbuf);
glob("../*.c", GLOB_DOOFFS | GLOB_APPEND, NULL, &globbuf);
globbuf.gl_pathv[0] = "ls";
globbuf.gl_pathv[1] = "-l";
execvp("ls", &globbuf.gl_pathv[0]);
SEE ALSO
ls(1), sh(1), stat(2), exec(3), fnmatch(3), malloc(3), opendir(3), readdir(3), wordexp(3), glob(7)
GNU 2021-03-22 GLOB(3)