DLERROR(3P)                                         POSIX Programmer's Manual                                        DLERROR(3P)



PROLOG
       This  manual  page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may differ (con-
       sult the corresponding Linux manual page for details of Linux behavior), or the  interface  may  not  be  implemented  on
       Linux.

NAME
       dlerror - get diagnostic information

SYNOPSIS
       #include <dlfcn.h>

       char *dlerror(void);


DESCRIPTION
       The  dlerror()  function  shall return a null-terminated character string (with no trailing <newline>) that describes the
       last error that occurred during dynamic linking processing. If no dynamic linking errors have  occurred  since  the  last
       invocation  of  dlerror(),  dlerror() shall return NULL.  Thus, invoking dlerror() a second time, immediately following a
       prior invocation, shall result in NULL being returned.

       The dlerror() function need not be reentrant. A function that is not required to be  reentrant  is  not  required  to  be
       thread-safe.

RETURN VALUE
       If successful, dlerror() shall return a null-terminated character string; otherwise, NULL shall be returned.

ERRORS
       No errors are defined.

       The following sections are informative.

EXAMPLES
       The following example prints out the last dynamic linking error:


              ...
              #include <dlfcn.h>


              char *errstr;


              errstr = dlerror();
              if (errstr != NULL)
              printf ("A dynamic linking error occurred: (%s)\n", errstr);
              ...

APPLICATION USAGE
       The messages returned by dlerror() may reside in a static buffer that is overwritten on each call to dlerror().  Applica-
       tion code should not write to this buffer. Programs wishing to preserve an error message should make their own copies  of
       that  message. Depending on the application environment with respect to asynchronous execution events, such as signals or
       other asynchronous computation sharing the address space, conforming  applications  should  use  a  critical  section  to
       retrieve the error pointer and buffer.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       dlclose(), dlopen(), dlsym(), the Base Definitions volume of IEEE Std 1003.1-2001, <dlfcn.h>

COPYRIGHT
       Portions  of  this  text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for
       Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6,  Copy-
       right (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any
       discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open  Group
       Standard   is   the   referee   document.   The   original   Standard   can   be   obtained  online  at  http://www.open-
       group.org/unix/online.html .



IEEE/The Open Group                                           2003                                                   DLERROR(3P)