path: root/man3/glob.3

'\" t
.\" Copyright (c) 1993 by Thomas Koenig (ig25@rz.uni-karlsruhe.de)
.\"
.\" SPDX-License-Identifier: Linux-man-pages-copyleft
.\"
.\" Modified Wed Jul 28 11:12:17 1993 by Rik Faith (faith@cs.unc.edu)
.\" Modified Mon May 13 23:08:50 1996 by Martin Schulze (joey@linux.de)
.\" Modified 11 May 1998 by Joseph S. Myers (jsm28@cam.ac.uk)
.\" Modified 990912 by aeb
.\" 2007-10-10 mtk
.\"     Added description of GLOB_TILDE_NOMATCH
.\"     Expanded the description of various flags
.\"     Various wording fixes.
.\"
.TH glob 3 (date) "Linux man-pages (unreleased)"
.SH NAME
glob, globfree \- find pathnames matching a pattern, free memory from glob()
.SH LIBRARY
Standard C library
.RI ( libc ", " \-lc )
.SH SYNOPSIS
.nf
.B #include <glob.h>
.PP
.BI "int glob(const char *restrict " pattern ", int " flags ,
.BI "         int (*" errfunc ")(const char *" epath ", int " eerrno ),
.BI "         glob_t *restrict " pglob );
.BI "void globfree(glob_t *" pglob );
.fi
.SH DESCRIPTION
The
.BR glob ()
function searches for all the pathnames matching
.I pattern
according to the rules used by the shell (see
.BR glob (7)).
No tilde expansion or parameter substitution is done; if you want
these, use
.BR wordexp (3).
.PP
The
.BR globfree ()
function frees the dynamically allocated storage from an earlier call
to
.BR glob ().
.PP
The results of a
.BR glob ()
call are stored in the structure pointed to by
.IR pglob .
This structure is of type
.I glob_t
(declared in
.IR <glob.h> )
and includes the following elements defined by POSIX.2 (more may be
present as an extension):
.PP
.in +4n
.EX
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 \fIgl_pathv\fP.  */
} glob_t;
.EE
.in
.PP
Results are stored in dynamically allocated storage.
.PP
The argument
.I flags
is made up of the bitwise OR of zero or more the following symbolic
constants, which modify the behavior of
.BR glob ():
.TP
.B GLOB_ERR
Return upon a read error (because a directory does not
have read permission, for example).
By default,
.BR glob ()
attempts carry on despite errors,
reading all of the directories that it can.
.TP
.B GLOB_MARK
Append a slash to each path which corresponds to a directory.
.TP
.B 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.
.TP
.B GLOB_DOOFFS
Reserve
.I pglob\->gl_offs
slots at the beginning of the list of strings in
.IR pglob\->pathv .
The reserved slots contain null pointers.
.TP
.B GLOB_NOCHECK
If no pattern matches, return the original pattern.
By default,
.BR glob ()
returns
.B GLOB_NOMATCH
if there are no matches.
.TP
.B GLOB_APPEND
Append the results of this call to the vector of results
returned by a previous call to
.BR glob ().
Do not set this flag on the first invocation of
.BR glob ().
.TP
.B GLOB_NOESCAPE
Don't allow backslash (\[aq]\e\[aq]) 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.
.PP
.I flags
may also include any of the following, which are GNU
extensions and not defined by POSIX.2:
.TP
.B GLOB_PERIOD
Allow a leading period to be matched by metacharacters.
By default, metacharacters can't match a leading period.
.TP
.B GLOB_ALTDIRFUNC
Use alternative functions
.IR pglob\->gl_closedir ,
.IR pglob\->gl_readdir ,
.IR pglob\->gl_opendir ,
.IR pglob\->gl_lstat ,
and
.I pglob\->gl_stat
for filesystem access instead of the normal library
functions.
.TP
.B GLOB_BRACE
Expand
.BR csh (1)
style brace expressions of the form
.BR {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
.BR glob ()
calls using the strings:
"foo/",
"foo/cat",
"foo/dog",
and
"bar".
.TP
.B 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.
.TP
.B GLOB_TILDE
Carry out tilde expansion.
If a tilde (\[aq]\[ti]\[aq]) is the only character in the pattern,
or an initial tilde is followed immediately by a slash (\[aq]/\[aq]),
then the home directory of the caller is substituted for
the tilde.
If an initial tilde is followed by a username (e.g., "\[ti]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.
.TP
.B GLOB_TILDE_CHECK
This provides behavior similar to that of
.BR 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,
.BR glob ()
returns
.B GLOB_NOMATCH
to indicate an error.
.TP
.B GLOB_ONLYDIR
This is a
.I hint
to
.BR 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.)
.PP
If
.I errfunc
is not NULL,
it will be called in case of an error with the arguments
.IR epath ,
a pointer to the path which failed, and
.IR eerrno ,
the value of
.I errno
as returned from one of the calls to
.BR opendir (3),
.BR readdir (3),
or
.BR stat (2).
If
.I errfunc
returns nonzero, or if
.B GLOB_ERR
is set,
.BR glob ()
will terminate after the call to
.IR errfunc .
.PP
Upon successful return,
.I pglob\->gl_pathc
contains the number of matched pathnames and
.I pglob\->gl_pathv
contains a pointer to the list of pointers to matched pathnames.
The list of pointers is terminated by a null pointer.
.PP
It is possible to call
.BR glob ()
several times.
In that case, the
.B GLOB_APPEND
flag has to be set in
.I flags
on the second and later invocations.
.PP
As a GNU extension,
.I pglob\->gl_flags
is set to the flags specified,
.BR or ed
with
.B GLOB_MAGCHAR
if any metacharacters were found.
.SH RETURN VALUE
On successful completion,
.BR glob ()
returns zero.
Other possible returns are:
.TP
.B GLOB_NOSPACE
for running out of memory,
.TP
.B GLOB_ABORTED
for a read error, and
.TP
.B GLOB_NOMATCH
for no found matches.
.SH ATTRIBUTES
For an explanation of the terms used in this section, see
.BR attributes (7).
.TS
allbox;
lb lb lbx
l l l.
Interface	Attribute	Value
T{
.na
.nh
.BR glob ()
T}	Thread safety	T{
.na
.nh
MT-Unsafe race:utent env
sig:ALRM timer locale
T}
T{
.na
.nh
.BR globfree ()
T}	Thread safety	MT-Safe
.TE
.sp 1
In the above table,
.I utent
in
.I race:utent
signifies that if any of the functions
.BR setutent (3),
.BR getutent (3),
or
.BR endutent (3)
are used in parallel in different threads of a program,
then data races could occur.
.BR glob ()
calls those functions,
so we use race:utent to remind users.
.SH STANDARDS
POSIX.1-2008.
.SH HISTORY
POSIX.1-2001, POSIX.2.
.SH NOTES
The structure elements
.I gl_pathc
and
.I gl_offs
are declared as
.I size_t
in glibc 2.1, as they should be according to POSIX.2,
but are declared as
.I int
in glibc 2.0.
.SH BUGS
The
.BR glob ()
function may fail due to failure of underlying function calls, such as
.BR malloc (3)
or
.BR opendir (3).
These will store their error code in
.IR errno .
.SH EXAMPLES
One example of use is the following code, which simulates typing
.PP
.in +4n
.EX
ls \-l *.c ../*.c
.EE
.in
.PP
in the shell:
.PP
.in +4n
.EX
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]);
.EE
.in
.SH SEE ALSO
.BR ls (1),
.BR sh (1),
.BR stat (2),
.BR exec (3),
.BR fnmatch (3),
.BR malloc (3),
.BR opendir (3),
.BR readdir (3),
.BR wordexp (3),
.BR glob (7)