Home Man
Today's Posts

Linux & Unix Commands - Search Man Pages
Man Page or Keyword Search:
Select Section of Man Page:
Select Man Page Repository:

Linux 2.6 - man page for globfree (linux section 3posix)

GLOB(P) 			    POSIX Programmer's Manual				  GLOB(P)

       glob, globfree - generate pathnames matching a pattern

       #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);

       The  glob() 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  Nota-
       tion,   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.

       The structure type glob_t is defined in <glob.h> and includes at least the following  mem-

		 Member Type Member Name Description
		 size_t      gl_pathc	 Count of paths matched by pattern.
		 char **     gl_pathv	 Pointer to a list of matched pathnames.
		 size_t      gl_offs	 Slots to reserve at the beginning of gl_pathv.

       The  argument  pattern is a pointer to a pathname pattern to be expanded. The glob() func-
       tion 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, glob() requires search per-
       mission on every component of a path except the last, and read permission on  each  direc-
       tory of any filename component of pattern that contains any of the following special char-
       acters: '*' , '?' , and '[' .

       The glob() function shall store the number of matched pathnames into pglob->gl_pathc and a
       pointer to a list of pointers to pathnames into pglob->gl_pathv. The pathnames shall be in
       sort order as defined by the current setting of the LC_COLLATE category; see the Base Def-
       initions  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  path-
       names,  the  returned  number  of  matched  paths  is  set  to  0,  and	the  contents  of
       pglob->gl_pathv are implementation-defined.

       It is the caller's responsibility to create the structure pointed to by pglob. The  glob()
       function  shall	allocate  other  space	as  needed,  including	the  memory pointed to by
       gl_pathv.  The globfree() function shall free any space associated with pglob from a  pre-
       vious call to glob().

       The  flags  argument  is  used to control the behavior of glob().  The value of flags is a
       bitwise-inclusive OR of zero or more of the following  constants,  which  are  defined  in

	      Append pathnames generated to the ones from a previous call to glob().

	      Make  use of pglob->gl_offs. If this flag is set, pglob->gl_offs is used to specify
	      how many null pointers to add to the beginning of pglob->gl_pathv.  In other words,
	      pglob->gl_pathv	shall	point	to  pglob->gl_offs  null  pointers,  followed  by
	      pglob->gl_pathc pathname pointers, followed by a null pointer.

	      Cause glob() to return when it encounters a directory that it cannot open or  read.
	      Ordinarily, glob() continues to find matches.

	      Each pathname that is a directory that matches pattern shall have a slash appended.

	      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 pattern does not match  any  path-
	      name, then glob() shall return a list consisting of only pattern, and the number of
	      matched pathnames is 1.

	      Disable backslash escaping.

	      Ordinarily, glob() sorts the matching pathnames according to the current setting of
	      the  LC_COLLATE  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.

       The GLOB_APPEND flag can be used to append a new set of pathnames to those found in a pre-
       vious call to glob(). The following rules apply to applications when two or more calls  to
       glob() are made with the same value of pglob and without intervening calls to globfree():

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

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

	3. After the second call, pglob->gl_pathv points to a list containing the following:

	    a. Zero or more null pointers, as specified by GLOB_DOOFFS and pglob->gl_offs.

	    b. Pointers  to  the pathnames that were in the pglob->gl_pathv list before the call,
	       in the same order as before.

	    c. Pointers to the new pathnames generated by  the	second	call,  in  the	specified

	4. The	count returned in pglob->gl_pathc shall be the total number of pathnames from the
	   two calls.

	5. The application can change any of the fields after a call to glob().  If it does,  the
	   application shall reset them to the original value before a subsequent call, using the
	   same pglob value, to globfree() or glob() with the GLOB_APPEND flag.

       If, during the search, a directory is encountered  that	cannot	be  opened  or	read  and
       errfunc is not a null pointer, glob() calls (*errfunc()) with two arguments:

	1. The epath argument is a pointer to the path that failed.

	2. The eerrno argument is the value of errno from the failure, as set by opendir(), read-
	   dir(), or stat(). (Other values may be used to report other errors not explicitly doc-
	   umented for those functions.)

       If  (*errfunc())  is called and returns non-zero, or if the GLOB_ERR flag is set in flags,
       glob() shall stop the scan and return GLOB_ABORTED after setting gl_pathc and gl_pathv  in
       pglob to reflect the paths already scanned. If GLOB_ERR is not set and either errfunc is a
       null pointer or (*errfunc()) returns 0, the error shall be ignored.

       The glob() function shall not fail because of large files.

       Upon successful completion, glob() shall return	0.  The  argument  pglob->gl_pathc  shall
       return  the  number  of matched pathnames and the argument pglob->gl_pathv shall contain a
       pointer	to  a  null-terminated	list  of  matched  and	sorted	pathnames.  However,   if
       pglob->gl_pathc is 0, the content of pglob->gl_pathv is undefined.

       The globfree() function shall not return a value.

       If  glob()  terminates  due  to	an  error,  it shall return one of the non-zero constants
       defined in <glob.h>. The arguments pglob->gl_pathc and pglob->gl_pathv are  still  set  as
       defined above.

       The glob() function shall fail and return the corresponding value if:

	      The scan was stopped because GLOB_ERR was set or (*errfunc()) returned non-zero.

	      The  pattern  does not match any existing pathname, and GLOB_NOCHECK was not set in

	      An attempt to allocate memory failed.

       The following sections are informative.

       One use of the GLOB_DOOFFS flag is by applications that build an  argument  list  for  use
       with  execv(),  execve(), or execvp().  Suppose, for example, that an application wants to
       do the equivalent of:

	      ls -l *.c

       but for some reason:

	      system("ls -l *.c")

       is not acceptable. The application could obtain approximately the same  result  using  the

	      globbuf.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]);

       Using the same example:

	      ls -l *.c *.h

       could be approximately simulated using GLOB_APPEND as follows:

	      globbuf.gl_offs = 2;
	      glob("*.c", GLOB_DOOFFS, NULL, &globbuf);
	      glob("*.h", GLOB_DOOFFS|GLOB_APPEND, NULL, &globbuf);

       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.

       If a utility needs to see if a pathname matches a given pattern, it can use fnmatch().

       Note  that  gl_pathc and gl_pathv have meaning even if glob() fails. This allows glob() to
       report partial results in the event of an error. However, if gl_pathc is  0,  gl_pathv  is
       unspecified even if glob() did not return an error.

       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 sh
       utility might use this for option-arguments, for example.

       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  expan-
       sion when multiple expansions are done on a command line.

       Applications that need tilde and parameter expansion should use wordexp().

       It  was	claimed  that  the  GLOB_DOOFFS flag is unnecessary because it could be simulated

	      new = (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 *));
	      pglob->gl_pathv = new;

       However, this assumes that the memory pointed to by gl_pathv is a  block  that  was  sepa-
       rately  created	using  malloc().  This is not necessarily the case. An application should
       make no assumptions about how the memory referenced by fields in pglob was allocated.   It
       might  have been obtained from malloc() in a large chunk and then carved up within glob(),
       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 glob() is managed.

       The  GLOB_APPEND  flag would be used when an application wants to expand several different
       patterns into a single list.


       exec() , fnmatch() , opendir() , readdir() , stat() , wordexp()	,  the	Base  Definitions
       volume	of   IEEE Std 1003.1-2001,   <glob.h>,	 the   Shell   and  Utilities  volume  of
       IEEE Std 1003.1-2001

       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 orig-
       inal Standard can be obtained online at http://www.opengroup.org/unix/online.html .

IEEE/The Open Group			       2003					  GLOB(P)

All times are GMT -4. The time now is 07:02 AM.

Unix & Linux Forums Content Copyrightę1993-2018. All Rights Reserved.
Show Password

Not a Forum Member?
Forgot Password?