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glibc  2.9
Functions
dirname.c File Reference
#include <libgen.h>
#include <string.h>

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Functions

char * dirname (char *path)

Function Documentation

char* dirname ( char *  path)

Definition at line 26 of file dirname.c.

{
  static const char dot[] = ".";
  char *last_slash;

  /* Find last '/'.  */
  last_slash = path != NULL ? strrchr (path, '/') : NULL;

  if (last_slash != NULL && last_slash != path && last_slash[1] == '\0')
    {
      /* Determine whether all remaining characters are slashes.  */
      char *runp;

      for (runp = last_slash; runp != path; --runp)
       if (runp[-1] != '/')
         break;

      /* The '/' is the last character, we have to look further.  */
      if (runp != path)
       last_slash = __memrchr (path, '/', runp - path);
    }

  if (last_slash != NULL)
    {
      /* Determine whether all remaining characters are slashes.  */
      char *runp;

      for (runp = last_slash; runp != path; --runp)
       if (runp[-1] != '/')
         break;

      /* Terminate the path.  */
      if (runp == path)
       {
         /* The last slash is the first character in the string.  We have to
            return "/".  As a special case we have to return "//" if there
            are exactly two slashes at the beginning of the string.  See
            XBD 4.10 Path Name Resolution for more information.  */
         if (last_slash == path + 1)
           ++last_slash;
         else
           last_slash = path + 1;
       }
      else
       last_slash = runp;

      last_slash[0] = '\0';
    }
  else
    /* This assignment is ill-designed but the XPG specs require to
       return a string containing "." in any case no directory part is
       found and so a static and constant string is required.  */
    path = (char *) dot;

  return path;
}

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