glob(3)
NAME
glob, globfree - find pathnames matching a pattern, free memory from
glob()
SYNOPSIS
#include <glob.h>
int glob(const char *pattern, int flags,
int (*errfunc) (const char *epath, int eerrno),
glob_t *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 substitution 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
username 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 purpose 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 returned 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 pathnames. 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.
EXAMPLE
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)
COLOPHON
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