glob, globfree: najděte cesty odpovídající vzoru, uvolněte paměť od glob ()

Originální popis anglicky: glob, globfree - find pathnames matching a pattern, free memory from glob()

Návod, kniha: Linux Programmer's Manual

STRUČNĚ

#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);

POPIS / INSTRUKCE

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, which is a glob_t which is 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 parameter flags is made up of bitwise OR of zero or more the following symbolic constants, which modify the of behaviour of glob():

GLOB_ERR

which means to return upon read error (because a directory does not have read permission, for example),

GLOB_MARK

which means to append a slash to each path which corresponds to a directory,

GLOB_NOSORT

which means don't sort the returned pathnames (they are by default),

GLOB_DOOFFS

which means that pglob->gl_offs slots will be reserved at the beginning of the list of strings in pglob->pathv,

GLOB_NOCHECK

which means that, if no pattern matches, to return the original pattern,

GLOB_APPEND

which means to append to the results of a previous call. Do not set this flag on the first invocation of glob().

GLOB_NOESCAPE

which means that meta characters cannot be quoted by backslashes.

The flags may also include some of the following, which are GNU extensions and not defined by POSIX.2:

GLOB_PERIOD

which means that a leading period can be matched by meta characters,

GLOB_ALTDIRFUNC

which means that alternative functions pglob->gl_closedir, pglob->gl_readdir, pglob->gl_opendir, pglob->gl_lstat, and pglob->gl_stat are used for file system access instead of the normal library functions,

GLOB_BRACE

which means that csh(1) style brace expresions {a,b} are expanded,

GLOB_NOMAGIC

which means that the pattern is returned if it contains no metacharacters,

GLOB_TILDE

which means that tilde expansion is carried out, and

GLOB_ONLYDIR

which means that only directories are matched.

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(), readdir(), or stat(). If errfunc returns non-zero, 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 a pointer to the list of matched pathnames. The first pointer after the last pathname is NULL. 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.

NÁVRATOVÁ HODNOTA

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.

PŘÍKLADY POUŽITÍ

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]);

ODPOVÍDAJÍCÍ

POSIX.2

BUGS

The glob() function may fail due to failure of underlying function calls, such as malloc() or opendir(). These will store their error code in errno.

NOTES

The structure elements gl_pathc and gl_offs are declared as size_t in glibc 2.1, as they should according to POSIX.2, but are declared as int in libc4, libc5 and glibc 2.0.

SOUVISEJÍCÍ

ls(1), sh(1), stat(2), exec(3), malloc(3), opendir(3), readdir(3), wordexp(3), glob(7)