ChorusOS man pages section 3POSIX: POSIX Library Functions

glob(3POSIX)

NAME

glob, globfree- generate pathnames matching a pattern

SYNOPSIS

#include <glob.h>

pattern

flags

errfunc

pglob

DESCRIPTION

The glob function is a pathname generator that implements the rules for file name pattern matching used by the shell.

The include file glob.h defines the structure type glob_t , which contains at least the following fields:

typedef struct {
    int     gl_pathc;       /* count of total paths so far */
    int     gl_matchc;      /* count of paths matching pattern */
    int     gl_offs;        /* reserved at beginning of gl_pathv */
    int     gl_flags;       /* returned flags */
    char    **gl_pathv;     /* list of paths matching pattern */
} glob_t;

The pattern argument is a pointer to a pathname pattern to be expanded. The glob argument matches all accessible pathnames against the pattern and creates a list of the pathnames that match. In order to have access to a pathname, glob requires search permission on every component of a path except the last, and read permission on each directory of any filename component of pattern that contains any of the special characters "*" , "?" or "[".

The glob argument stores the number of matched pathnames in the gl_pathc field, and a pointer to a list of pointers to pathnames in the gl_pathv field. The first pointer after the last pathname is NULL . If the pattern does not match any pathnames, the number of matched paths returned is set to zero.

It is the caller's responsibility to create the structure pointed to by pglob . The glob function allocates other space as needed, including the memory pointed to by gl_pathv .

The flags argument is used to modify the behavior of glob . The value of flags is the bitwise inclusive OR of any of the following values defined in glob.h :

GLOB_APPEND: Append pathnames generated to any from a previous call (or calls) to glob . The value of gl_pathc will be the total matches found by this call and the previous call(s). The pathnames are appended to, not merged with, the pathnames returned by the previous call(s). Between calls, the caller must not change the setting of the GLOB_DOOFFS flag, nor change the value of gl_offs when GLOB_DOOFFS is set, nor call globfree for pglob .
GLOB_DOOFFS: Use the gl_offs field. If this flag is set, gl_offs is used to specify how many NULL pointers to prepend to the beginning of the gl_pathv field. In other words, gl_pathv will point to gl_offs NULL pointers, followed by gl_pathc pathname pointers, followed by a NULL pointer.
GLOB_ERR: Causes glob to return when it encounters a directory that it cannot open or read. Ordinarily, glob continues to find matches.
GLOB_MARK: Each pathname that is a directory that matches pattern has a slash appended.
GLOB_NOCHECK: If pattern does not match any pathname, glob returns a list consisting of only pattern with the total number of pathnames set to 1, and the number of matched pathnames set to 0. If GLOB_QUOTE is set, its effect is present in the pattern returned.
GLOB_NOSORT: By default, the pathnames are sorted in ascending ASCII order; this flag prevents that sorting (speeding up glob ) .

The following values may also be included in flags , however, they are non-standard extensions to POSIX 1003.2 .

GLOB_ALTDIRFUNC: The following additional fields in the pglob structure have been initialized with alternate functions for glob to use to open, read, and close directories and to get stat information on names found in those directories.

void*             (*gl_opendir)(const char* name);
struct dirent*    (*gl_readdir)(void*);
void              (*gl_closedir)(void*);
int               (*gl_lstat)(const char* name, struct stat* st);
int               (*gl_stat)(const char* name, struct stat* st);

GLOB_BRACE: Pre-process the pattern string to expand {pat,pat,.... The "{" pattern is left unexpanded for historical reasons.
GLOB_MAGCHAR: Set by the glob function if the pattern included globbing characters. See the description of the usage of the gl_matchc structure member for more details.
GLOB_NOMAGIC: Is the same as GLOB_NOCHECK but it only appends the pattern if it does not contain any of the special characters ``*'', ``?'' or ``[''.
GLOB_QUOTE: Use the backslash" \\" character for quoting: every occurrence of a backslash followed by a character in the pattern. This will be replaced by that character, avoiding any special interpretation of the character.
GLOB_TILDE: Expand patterns that start with a tilde ("~") to user name home directories.

If, during the search, a directory is encountered that cannot be opened or read and errfunc is non-NULL , glob calls (*errfunc)(path, errno) . This may be an unintuitive: pattern like */Makefile will try to stat(2POSIX) foo/Makefile even if foo is not a directory, resulting in a call to errfunc . The error routine can suppress this action by testing for ENOENT and ENOTDIR ; however, the GLOB_ERR flag will still cause an immediate return when this happens.

If errfunc returns non-zero, glob stops the scan and returns GLOB_ABEND after setting gl_pathc and gl_pathv to reflect any paths already matched. This also happens if an error is encountered and GLOB_ERR is set in flags , regardless of the return value of errfunc , if called. If GLOB_ERR is not set and either errfunc is NULL or errfunc returns zero, the error is ignored.

The globfree function frees any space associated with pglob from any previous call(s) to glob .

RETURN VALUES

On successful completion, glob returns zero. In addition the fields of pglob contain the values described below:

gl_pathc: contains the total number of pathnames matched so far. This includes other matches from previous invocations of glob if GLOB_APPEND was specified.
gl_matchc: contains the number of matched pathnames in the current invocation of glob .
gl_flags: contains a copy of the flags parameter with the GLOB_MAGCHAR bit set if pattern contained any of the special characters ``*'', ``?'' or ``[''. If not, it is cleared.
gl_pathv: contains a pointer to a NULL terminated list of matched pathnames. However, if gl_pathc is zero, the contents of gl_pathv are undefined.

If glob terminates due to an error, it sets errno and returns one of the following non-zero constants, which are defined in the include file glob.h :

GLOB_NOSPACE: An attempt to allocate memory failed.
GLOB_ABEND: The scan was stopped because an error was encountered and either GLOB_ERR was set or (*errfunc)() returned a non-zero value.

The arguments pglob->gl_pathc and pglob->gl_pathv are still set as specified above.

STANDARDS

The glob function is POSIX 1003.2 compatible with the exception that the flags GLOB_ALTDIRFUNC , GLOB_BRACE , GLOB_MAGCHAR , GLOB_NOMAGIC , GLOB_QUOTE and GLOB_TILDE and the fields gl_matchc and gl_flags should not be used by applications which require strict POSIX conformance.

HISTORY

The glob and globfree functions first appeared in 4.4BSD.

BUGS

Patterns longer than MAXPATHLEN may cause unchecked errors.

The glob argument may fail and set errno for any of the errors specified for the library routines stat(2POSIX), closedir(3POSIX), opendir(3POSIX), readdir(3POSIX), malloc(3STDC), and free(3STDC).

RESTRICTIONS FOR ChorusOS

These library calls do not support multi-threaded applications.

ATTRIBUTES

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPE	ATTRIBUTE VALUE
Interface Stability	Evolving

ChorusOS 4.0 Last Revised December 1999