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| <a name="Calling-Glob"></a> |
| <p> |
| Next: <a rel="next" accesskey="n" href="Flags-for-Globbing.html#Flags-for-Globbing">Flags for Globbing</a>, |
| Up: <a rel="up" accesskey="u" href="Globbing.html#Globbing">Globbing</a> |
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| |
| <h4 class="subsection">10.2.1 Calling <code>glob</code></h4> |
| |
| <p>The result of globbing is a vector of file names (strings). To return |
| this vector, <code>glob</code> uses a special data type, <code>glob_t</code>, which |
| is a structure. You pass <code>glob</code> the address of the structure, and |
| it fills in the structure's fields to tell you about the results. |
| |
| <!-- glob.h --> |
| <!-- POSIX.2 --> |
| <div class="defun"> |
| — Data Type: <b>glob_t</b><var><a name="index-glob_005ft-853"></a></var><br> |
| <blockquote><p>This data type holds a pointer to a word vector. More precisely, it |
| records both the address of the word vector and its size. The GNU |
| implementation contains some more fields which are non-standard |
| extensions. |
| |
| <dl> |
| <dt><code>gl_pathc</code><dd>The number of elements in the vector, excluding the initial null entries |
| if the GLOB_DOOFFS flag is used (see gl_offs below). |
| |
| <br><dt><code>gl_pathv</code><dd>The address of the vector. This field has type <code>char **</code><!-- /@w -->. |
| |
| <br><dt><code>gl_offs</code><dd>The offset of the first real element of the vector, from its nominal |
| address in the <code>gl_pathv</code> field. Unlike the other fields, this |
| is always an input to <code>glob</code>, rather than an output from it. |
| |
| <p>If you use a nonzero offset, then that many elements at the beginning of |
| the vector are left empty. (The <code>glob</code> function fills them with |
| null pointers.) |
| |
| <p>The <code>gl_offs</code> field is meaningful only if you use the |
| <code>GLOB_DOOFFS</code> flag. Otherwise, the offset is always zero |
| regardless of what is in this field, and the first real element comes at |
| the beginning of the vector. |
| |
| <br><dt><code>gl_closedir</code><dd>The address of an alternative implementation of the <code>closedir</code> |
| function. It is used if the <code>GLOB_ALTDIRFUNC</code> bit is set in |
| the flag parameter. The type of this field is |
| <code>void (*) (void *)</code><!-- /@w -->. |
| |
| <p>This is a GNU extension. |
| |
| <br><dt><code>gl_readdir</code><dd>The address of an alternative implementation of the <code>readdir</code> |
| function used to read the contents of a directory. It is used if the |
| <code>GLOB_ALTDIRFUNC</code> bit is set in the flag parameter. The type of |
| this field is <code>struct dirent *(*) (void *)</code><!-- /@w -->. |
| |
| <p>This is a GNU extension. |
| |
| <br><dt><code>gl_opendir</code><dd>The address of an alternative implementation of the <code>opendir</code> |
| function. It is used if the <code>GLOB_ALTDIRFUNC</code> bit is set in |
| the flag parameter. The type of this field is |
| <code>void *(*) (const char *)</code><!-- /@w -->. |
| |
| <p>This is a GNU extension. |
| |
| <br><dt><code>gl_stat</code><dd>The address of an alternative implementation of the <code>stat</code> function |
| to get information about an object in the filesystem. It is used if the |
| <code>GLOB_ALTDIRFUNC</code> bit is set in the flag parameter. The type of |
| this field is <code>int (*) (const char *, struct stat *)</code><!-- /@w -->. |
| |
| <p>This is a GNU extension. |
| |
| <br><dt><code>gl_lstat</code><dd>The address of an alternative implementation of the <code>lstat</code> |
| function to get information about an object in the filesystems, not |
| following symbolic links. It is used if the <code>GLOB_ALTDIRFUNC</code> bit |
| is set in the flag parameter. The type of this field is <code>int (*) (const char *,<!-- /@w --> struct stat *)<!-- /@w --></code>. |
| |
| <p>This is a GNU extension. |
| </dl> |
| </p></blockquote></div> |
| |
| <p>For use in the <code>glob64</code> function <samp><span class="file">glob.h</span></samp> contains another |
| definition for a very similar type. <code>glob64_t</code> differs from |
| <code>glob_t</code> only in the types of the members <code>gl_readdir</code>, |
| <code>gl_stat</code>, and <code>gl_lstat</code>. |
| |
| <!-- glob.h --> |
| <!-- GNU --> |
| <div class="defun"> |
| — Data Type: <b>glob64_t</b><var><a name="index-glob64_005ft-854"></a></var><br> |
| <blockquote><p>This data type holds a pointer to a word vector. More precisely, it |
| records both the address of the word vector and its size. The GNU |
| implementation contains some more fields which are non-standard |
| extensions. |
| |
| <dl> |
| <dt><code>gl_pathc</code><dd>The number of elements in the vector, excluding the initial null entries |
| if the GLOB_DOOFFS flag is used (see gl_offs below). |
| |
| <br><dt><code>gl_pathv</code><dd>The address of the vector. This field has type <code>char **</code><!-- /@w -->. |
| |
| <br><dt><code>gl_offs</code><dd>The offset of the first real element of the vector, from its nominal |
| address in the <code>gl_pathv</code> field. Unlike the other fields, this |
| is always an input to <code>glob</code>, rather than an output from it. |
| |
| <p>If you use a nonzero offset, then that many elements at the beginning of |
| the vector are left empty. (The <code>glob</code> function fills them with |
| null pointers.) |
| |
| <p>The <code>gl_offs</code> field is meaningful only if you use the |
| <code>GLOB_DOOFFS</code> flag. Otherwise, the offset is always zero |
| regardless of what is in this field, and the first real element comes at |
| the beginning of the vector. |
| |
| <br><dt><code>gl_closedir</code><dd>The address of an alternative implementation of the <code>closedir</code> |
| function. It is used if the <code>GLOB_ALTDIRFUNC</code> bit is set in |
| the flag parameter. The type of this field is |
| <code>void (*) (void *)</code><!-- /@w -->. |
| |
| <p>This is a GNU extension. |
| |
| <br><dt><code>gl_readdir</code><dd>The address of an alternative implementation of the <code>readdir64</code> |
| function used to read the contents of a directory. It is used if the |
| <code>GLOB_ALTDIRFUNC</code> bit is set in the flag parameter. The type of |
| this field is <code>struct dirent64 *(*) (void *)</code><!-- /@w -->. |
| |
| <p>This is a GNU extension. |
| |
| <br><dt><code>gl_opendir</code><dd>The address of an alternative implementation of the <code>opendir</code> |
| function. It is used if the <code>GLOB_ALTDIRFUNC</code> bit is set in |
| the flag parameter. The type of this field is |
| <code>void *(*) (const char *)</code><!-- /@w -->. |
| |
| <p>This is a GNU extension. |
| |
| <br><dt><code>gl_stat</code><dd>The address of an alternative implementation of the <code>stat64</code> function |
| to get information about an object in the filesystem. It is used if the |
| <code>GLOB_ALTDIRFUNC</code> bit is set in the flag parameter. The type of |
| this field is <code>int (*) (const char *, struct stat64 *)</code><!-- /@w -->. |
| |
| <p>This is a GNU extension. |
| |
| <br><dt><code>gl_lstat</code><dd>The address of an alternative implementation of the <code>lstat64</code> |
| function to get information about an object in the filesystems, not |
| following symbolic links. It is used if the <code>GLOB_ALTDIRFUNC</code> bit |
| is set in the flag parameter. The type of this field is <code>int (*) (const char *,<!-- /@w --> struct stat64 *)<!-- /@w --></code>. |
| |
| <p>This is a GNU extension. |
| </dl> |
| </p></blockquote></div> |
| |
| <!-- glob.h --> |
| <!-- POSIX.2 --> |
| <div class="defun"> |
| — Function: int <b>glob</b> (<var>const char *pattern, int flags, int </var>(<var>*errfunc</var>) (<var>const char *filename, int error-code</var>)<var>, glob_t *vector-ptr</var>)<var><a name="index-glob-855"></a></var><br> |
| <blockquote><p>The function <code>glob</code> does globbing using the pattern <var>pattern</var> |
| in the current directory. It puts the result in a newly allocated |
| vector, and stores the size and address of this vector into |
| <code>*</code><var>vector-ptr</var>. The argument <var>flags</var> is a combination of |
| bit flags; see <a href="Flags-for-Globbing.html#Flags-for-Globbing">Flags for Globbing</a>, for details of the flags. |
| |
| <p>The result of globbing is a sequence of file names. The function |
| <code>glob</code> allocates a string for each resulting word, then |
| allocates a vector of type <code>char **</code> to store the addresses of |
| these strings. The last element of the vector is a null pointer. |
| This vector is called the <dfn>word vector</dfn>. |
| |
| <p>To return this vector, <code>glob</code> stores both its address and its |
| length (number of elements, not counting the terminating null pointer) |
| into <code>*</code><var>vector-ptr</var>. |
| |
| <p>Normally, <code>glob</code> sorts the file names alphabetically before |
| returning them. You can turn this off with the flag <code>GLOB_NOSORT</code> |
| if you want to get the information as fast as possible. Usually it's |
| a good idea to let <code>glob</code> sort them—if you process the files in |
| alphabetical order, the users will have a feel for the rate of progress |
| that your application is making. |
| |
| <p>If <code>glob</code> succeeds, it returns 0. Otherwise, it returns one |
| of these error codes: |
| |
| <dl> |
| <!-- glob.h --> |
| <!-- POSIX.2 --> |
| <dt><code>GLOB_ABORTED</code><a name="index-GLOB_005fABORTED-856"></a><dd>There was an error opening a directory, and you used the flag |
| <code>GLOB_ERR</code> or your specified <var>errfunc</var> returned a nonzero |
| value. |
| for an explanation of the <code>GLOB_ERR</code> flag and <var>errfunc</var>. |
| |
| <!-- glob.h --> |
| <!-- POSIX.2 --> |
| <br><dt><code>GLOB_NOMATCH</code><a name="index-GLOB_005fNOMATCH-857"></a><dd>The pattern didn't match any existing files. If you use the |
| <code>GLOB_NOCHECK</code> flag, then you never get this error code, because |
| that flag tells <code>glob</code> to <em>pretend</em> that the pattern matched |
| at least one file. |
| |
| <!-- glob.h --> |
| <!-- POSIX.2 --> |
| <br><dt><code>GLOB_NOSPACE</code><a name="index-GLOB_005fNOSPACE-858"></a><dd>It was impossible to allocate memory to hold the result. |
| </dl> |
| |
| <p>In the event of an error, <code>glob</code> stores information in |
| <code>*</code><var>vector-ptr</var> about all the matches it has found so far. |
| |
| <p>It is important to notice that the <code>glob</code> function will not fail if |
| it encounters directories or files which cannot be handled without the |
| LFS interfaces. The implementation of <code>glob</code> is supposed to use |
| these functions internally. This at least is the assumptions made by |
| the Unix standard. The GNU extension of allowing the user to provide |
| own directory handling and <code>stat</code> functions complicates things a |
| bit. If these callback functions are used and a large file or directory |
| is encountered <code>glob</code> <em>can</em> fail. |
| </p></blockquote></div> |
| |
| <!-- glob.h --> |
| <!-- GNU --> |
| <div class="defun"> |
| — Function: int <b>glob64</b> (<var>const char *pattern, int flags, int </var>(<var>*errfunc</var>) (<var>const char *filename, int error-code</var>)<var>, glob64_t *vector-ptr</var>)<var><a name="index-glob64-859"></a></var><br> |
| <blockquote><p>The <code>glob64</code> function was added as part of the Large File Summit |
| extensions but is not part of the original LFS proposal. The reason for |
| this is simple: it is not necessary. The necessity for a <code>glob64</code> |
| function is added by the extensions of the GNU <code>glob</code> |
| implementation which allows the user to provide own directory handling |
| and <code>stat</code> functions. The <code>readdir</code> and <code>stat</code> functions |
| do depend on the choice of <code>_FILE_OFFSET_BITS</code> since the definition |
| of the types <code>struct dirent</code> and <code>struct stat</code> will change |
| depending on the choice. |
| |
| <p>Beside this difference the <code>glob64</code> works just like <code>glob</code> in |
| all aspects. |
| |
| <p>This function is a GNU extension. |
| </p></blockquote></div> |
| |
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