~ubuntu-branches/ubuntu/precise/manpages-posix/precise

.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved 

.TH "GLOB" P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"

.\" glob 

.SH NAME

glob, globfree \- generate pathnames matching a pattern

.SH SYNOPSIS

.LP

\fB#include <glob.h>

.br

.sp

int glob(const char *restrict\fP \fIpattern\fP\fB, int\fP \fIflags\fP\fB,

.br

\ \ \ \ \ \  int(*\fP\fIerrfunc\fP\fB)(const char *\fP\fIepath\fP\fB,

int\fP

\fIeerrno\fP\fB),

.br

\ \ \ \ \ \  glob_t *restrict\fP \fIpglob\fP\fB);

.br

void globfree(glob_t *\fP\fIpglob\fP\fB);

.br

\fP

.SH DESCRIPTION

.LP

The \fIglob\fP() function is a pathname generator that shall implement

the rules defined in the Shell and Utilities volume of

IEEE\ Std\ 1003.1-2001, Section 2.13, Pattern Matching Notation, with

optional support for rule 3 in the Shell and Utilities volume of IEEE\ Std\ 1003.1-2001,

Section 2.13.3, Patterns Used for Filename Expansion.

.LP

The structure type \fBglob_t\fP is defined in \fI<glob.h>\fP and includes

at least

the following members:

.TS C

center; l1 l1 l.

\fBMember Type\fP	\fBMember Name\fP	\fBDescription\fP

\fBsize_t\fP	\fIgl_pathc\fP	Count of paths matched by \fIpattern\fP.

\fBchar **\fP	\fIgl_pathv\fP	Pointer to a list of matched pathnames.

\fBsize_t\fP	\fIgl_offs\fP	Slots to reserve at the beginning of \fIgl_pathv\fP.

.TE

.LP

The argument \fIpattern\fP is a pointer to a pathname pattern to be

expanded. The \fIglob\fP() function shall match all

accessible pathnames against this pattern and develop a list of all

pathnames that match. In order to have access to a pathname,

\fIglob\fP() requires search permission on every component of a path

except the last, and read permission on each directory of any

filename component of \fIpattern\fP that contains any of the following

special characters: \fB'*'\fP , \fB'?'\fP , and

\fB'['\fP .

.LP

The \fIglob\fP() function shall store the number of matched pathnames

into \fIpglob\fP->\fIgl_pathc\fP and a pointer to a

list of pointers to pathnames into \fIpglob\fP->\fIgl_pathv\fP. The

pathnames shall be in sort order as defined by the current

setting of the \fILC_COLLATE\fP category; see the Base Definitions

volume of IEEE\ Std\ 1003.1-2001, Section 7.3.2, LC_COLLATE. The first

pointer after the last pathname shall be a null

pointer. If the pattern does not match any pathnames, the returned

number of matched paths is set to 0, and the contents of

\fIpglob\fP->\fIgl_pathv\fP are implementation-defined.

.LP

It is the caller's responsibility to create the structure pointed

to by \fIpglob\fP. The \fIglob\fP() function shall allocate

other space as needed, including the memory pointed to by \fIgl_pathv\fP.

The \fIglobfree\fP() function shall free any space

associated with \fIpglob\fP from a previous call to \fIglob\fP().

.LP

The \fIflags\fP argument is used to control the behavior of \fIglob\fP().

The value of \fIflags\fP is a bitwise-inclusive OR

of zero or more of the following constants, which are defined in \fI<glob.h>\fP:

.TP 7

GLOB_APPEND

Append pathnames generated to the ones from a previous call to \fIglob\fP().

.TP 7

GLOB_DOOFFS

Make use of \fIpglob\fP->\fIgl_offs\fP. If this flag is set, \fIpglob\fP->\fIgl_offs\fP

is used to specify how many

null pointers to add to the beginning of \fIpglob\fP->\fIgl_pathv\fP.

In other words, \fIpglob\fP->\fIgl_pathv\fP shall

point to \fIpglob\fP->\fIgl_offs\fP null pointers, followed by \fIpglob\fP->\fIgl_pathc\fP

pathname pointers, followed by

a null pointer.

.TP 7

GLOB_ERR

Cause \fIglob\fP() to return when it encounters a directory that it

cannot open or read. Ordinarily, \fIglob\fP() continues

to find matches.

.TP 7

GLOB_MARK

Each pathname that is a directory that matches \fIpattern\fP shall

have a slash appended.

.TP 7

GLOB_NOCHECK

Supports rule 3 in the Shell and Utilities volume of IEEE\ Std\ 1003.1-2001,

Section 2.13.3, Patterns Used for Filename Expansion. If \fIpattern\fP

does not

match any pathname, then \fIglob\fP() shall return a list consisting

of only \fIpattern\fP, and the number of matched pathnames

is 1.

.TP 7

GLOB_NOESCAPE

Disable backslash escaping.

.TP 7

GLOB_NOSORT

Ordinarily, \fIglob\fP() sorts the matching pathnames according to

the current setting of the \fILC_COLLATE\fP category; see

the Base Definitions volume of IEEE\ Std\ 1003.1-2001, Section 7.3.2,

LC_COLLATE. When this flag is used, the order of pathnames returned

is unspecified.

.sp

.LP

The GLOB_APPEND flag can be used to append a new set of pathnames

to those found in a previous call to \fIglob\fP(). The

following rules apply to applications when two or more calls to \fIglob\fP()

are made with the same value of \fIpglob\fP and

without intervening calls to \fIglobfree\fP():

.IP " 1." 4

The first such call shall not set GLOB_APPEND. All subsequent calls

shall set it.

.LP

.IP " 2." 4

All the calls shall set GLOB_DOOFFS, or all shall not set it.

.LP

.IP " 3." 4

After the second call, \fIpglob\fP->\fIgl_pathv\fP points to a list

containing the following:

.RS

.IP " a." 4

Zero or more null pointers, as specified by GLOB_DOOFFS and \fIpglob\fP->\fIgl_offs\fP.

.LP

.IP " b." 4

Pointers to the pathnames that were in the \fIpglob\fP->\fIgl_pathv\fP

list before the call, in the same order as

before.

.LP

.IP " c." 4

Pointers to the new pathnames generated by the second call, in the

specified order.

.LP

.RE

.LP

.IP " 4." 4

The count returned in \fIpglob\fP->\fIgl_pathc\fP shall be the total

number of pathnames from the two calls.

.LP

.IP " 5." 4

The application can change any of the fields after a call to \fIglob\fP().

If it does, the application shall reset them to the

original value before a subsequent call, using the same \fIpglob\fP

value, to \fIglobfree\fP() or \fIglob\fP() with the

GLOB_APPEND flag.

.LP

.LP

If, during the search, a directory is encountered that cannot be opened

or read and \fIerrfunc\fP is not a null pointer,

\fIglob\fP() calls (\fI*errfunc\fP()) with two arguments:

.IP " 1." 4

The \fIepath\fP argument is a pointer to the path that failed.

.LP

.IP " 2." 4

The \fIeerrno\fP argument is the value of \fIerrno\fP from the failure,

as set by \fIopendir\fP(), \fIreaddir\fP(), or \fIstat\fP(). (Other

values may be used to report other errors not explicitly documented

for those

functions.)

.LP

.LP

If (\fI*errfunc\fP()) is called and returns non-zero, or if the GLOB_ERR

flag is set in \fIflags\fP, \fIglob\fP() shall stop

the scan and return GLOB_ABORTED after setting \fIgl_pathc\fP and

\fIgl_pathv\fP in \fIpglob\fP to reflect the paths already

scanned. If GLOB_ERR is not set and either \fIerrfunc\fP is a null

pointer or (\fI*errfunc\fP()) returns 0, the error shall be

ignored.

.LP

The \fIglob\fP() function shall not fail because of large files.

.SH RETURN VALUE

.LP

Upon successful completion, \fIglob\fP() shall return 0. The argument

\fIpglob\fP->\fIgl_pathc\fP shall return the number

of matched pathnames and the argument \fIpglob\fP->\fIgl_pathv\fP

shall contain a pointer to a null-terminated list of matched

and sorted pathnames. However, if \fIpglob\fP->\fIgl_pathc\fP is 0,

the content of \fIpglob\fP->\fIgl_pathv\fP is

undefined.

.LP

The \fIglobfree\fP() function shall not return a value.

.LP

If \fIglob\fP() terminates due to an error, it shall return one of

the non-zero constants defined in \fI<glob.h>\fP. The arguments \fIpglob\fP->\fIgl_pathc\fP

and

\fIpglob\fP->\fIgl_pathv\fP are still set as defined above.

.SH ERRORS

.LP

The \fIglob\fP() function shall fail and return the corresponding

value if:

.TP 7

GLOB_ABORTED

The scan was stopped because GLOB_ERR was set or (\fI*errfunc\fP())

returned non-zero.

.TP 7

GLOB_NOMATCH

The pattern does not match any existing pathname, and GLOB_NOCHECK

was not set in flags.

.TP 7

GLOB_NOSPACE

An attempt to allocate memory failed.

.sp

.LP

\fIThe following sections are informative.\fP

.SH EXAMPLES

.LP

One use of the GLOB_DOOFFS flag is by applications that build an argument

list for use with \fIexecv\fP(), \fIexecve\fP(), or \fIexecvp\fP().

Suppose, for example, that an application wants to do the equivalent

of:

.sp

.RS

.nf

\fBls -l *.c

\fP

.fi

.RE

.LP

but for some reason:

.sp

.RS

.nf

\fBsystem("ls -l *.c")

\fP

.fi

.RE

.LP

is not acceptable. The application could obtain approximately the

same result using the sequence:

.sp

.RS

.nf

\fBglobbuf.gl_offs = 2;

glob("*.c", GLOB_DOOFFS, NULL, &globbuf);

globbuf.gl_pathv[0] = "ls";

globbuf.gl_pathv[1] = "-l";

execvp("ls", &globbuf.gl_pathv[0]);

\fP

.fi

.RE

.LP

Using the same example:

.sp

.RS

.nf

\fBls -l *.c *.h

\fP

.fi

.RE

.LP

could be approximately simulated using GLOB_APPEND as follows:

.sp

.RS

.nf

\fBglobbuf.gl_offs = 2;

glob("*.c", GLOB_DOOFFS, NULL, &globbuf);

glob("*.h", GLOB_DOOFFS|GLOB_APPEND, NULL, &globbuf);

\&...

\fP

.fi

.RE

.SH APPLICATION USAGE

.LP

This function is not provided for the purpose of enabling utilities

to perform pathname expansion on their arguments, as this

operation is performed by the shell, and utilities are explicitly

not expected to redo this. Instead, it is provided for

applications that need to do pathname expansion on strings obtained

from other sources, such as a pattern typed by a user or read

from a file.

.LP

If a utility needs to see if a pathname matches a given pattern, it

can use \fIfnmatch\fP().

.LP

Note that \fIgl_pathc\fP and \fIgl_pathv\fP have meaning even if \fIglob\fP()

fails. This allows \fIglob\fP() to report

partial results in the event of an error. However, if \fIgl_pathc\fP

is 0, \fIgl_pathv\fP is unspecified even if \fIglob\fP()

did not return an error.

.LP

The GLOB_NOCHECK option could be used when an application wants to

expand a pathname if wildcards are specified, but wants to

treat the pattern as just a string otherwise. The \fIsh\fP utility

might use this for

option-arguments, for example.

.LP

The new pathnames generated by a subsequent call with GLOB_APPEND

are not sorted together with the previous pathnames. This

mirrors the way that the shell handles pathname expansion when multiple

expansions are done on a command line.

.LP

Applications that need tilde and parameter expansion should use \fIwordexp\fP().

.SH RATIONALE

.LP

It was claimed that the GLOB_DOOFFS flag is unnecessary because it

could be simulated using:

.sp

.RS

.nf

\fBnew = (char **)malloc((n + pglob->gl_pathc + 1)

       * sizeof(char *));

(void) memcpy(new+n, pglob->gl_pathv,

       pglob->gl_pathc * sizeof(char *));

(void) memset(new, 0, n * sizeof(char *));

free(pglob->gl_pathv);

pglob->gl_pathv = new;

\fP

.fi

.RE

.LP

However, this assumes that the memory pointed to by \fIgl_pathv\fP

is a block that was separately created using \fImalloc\fP(). This

is not necessarily the case. An application should make no assumptions

about

how the memory referenced by fields in \fIpglob\fP was allocated.

It might have been obtained from \fImalloc\fP() in a large chunk and

then carved up within \fIglob\fP(), or it might have been

created using a different memory allocator. It is not the intent of

the standard developers to specify or imply how the memory used

by \fIglob\fP() is managed.

.LP

The GLOB_APPEND flag would be used when an application wants to expand

several different patterns into a single list.

.SH FUTURE DIRECTIONS

.LP

None.

.SH SEE ALSO

.LP

\fIexec\fP() , \fIfnmatch\fP() , \fIopendir\fP() , \fIreaddir\fP()

, \fIstat\fP() , \fIwordexp\fP() , the Base Definitions volume of

IEEE\ Std\ 1003.1-2001, \fI<glob.h>\fP, the Shell and Utilities volume

of IEEE\ Std\ 1003.1-2001

.SH COPYRIGHT

Portions of this text are reprinted and reproduced in electronic form

from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology

-- Portable Operating System Interface (POSIX), The Open Group Base

Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of

Electrical and Electronics Engineers, Inc and The Open Group. In the

event of any discrepancy between this version and the original IEEE and

The Open Group Standard, the original IEEE and The Open Group Standard

is the referee document. The original Standard can be obtained online at

http://www.opengroup.org/unix/online.html .