Databases
StackOverflow2013
Postsdbo
POWhat guarantees does pathconf(..., _PC_NAME_MAX) provide?
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POWhat guarantees does pathconf(..., _PC_NAME_MAX) provide?
    primarykey
    data
    text
    <p><strong>Context:</strong></p> <p>The <a href="http://linux.die.net/man/3/readdir_r" rel="nofollow"><code>readdir_r</code></a> function is used to read the next entry from a <code>DIR*</code> (there's also <code>readdir</code>, but that's not thread-safe). <code>readdir_r</code> takes a pointer to a user-allocated buffer to hold the output <code>dirent</code>. The manpage indicates that the size required for this buffer may be different on different systems, and provides an example of how to find a safe length at runtime:</p> <pre><code>len = offsetof(struct dirent, d_name) + pathconf(dirpath, _PC_NAME_MAX) + 1; </code></pre> <p>(warning: there is a race condition in the above, which can be avoided by using <code>dirfd</code> to get the file descriptor for the opened <code>DIR*</code> and using <code>fpathconf</code> instead of <code>pathconf</code>)</p> <p><strong>Question:</strong></p> <p>Looking at the manpage for <a href="http://linux.die.net/man/3/pathconf" rel="nofollow"><code>pathconf</code></a>, it states:</p> <blockquote> <p><strong>_PC_NAME_MAX</strong> returns the maximum length of a filename in the directory path or fd that the process is allowed to create. The corresponding macro is _POSIX_NAME_MAX.</p> </blockquote> <p>However, in the notes section, it states:</p> <blockquote> <p>Files with name lengths longer than the value returned for name equal to _PC_NAME_MAX may exist in the given directory.</p> </blockquote> <p>Is this note true? If so, is the example code in the <code>readdir_r</code> man-page incorrect?</p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USJohn Bartholomew
    1. USJohn Bartholomew
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POWhat guarantees does pathconf(..., _PC_NAME_MAX) provide?
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. POWhat guarantees does pathconf(..., _PC_NAME_MAX) provide?
      1. USJames Caccese
      1. VTFavorite
    1. This table or related slice is empty.
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload