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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 (consult 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.
       It  is  implementation-defined whether or not the dlerror() function is
       thread-safe. A thread-safe implementation shall return only errors that
       occur on the current thread.
RETURN VALUE
       If  successful,  dlerror()  shall  return  a  null-terminated character
       string; otherwise, NULL shall be returned.
       The application shall not modify  the  string  returned.  The  returned
       pointer might be invalidated or the string content might be overwritten
       by a subsequent call to dlerror() in the same thread (if  dlerror()  is
       thread-safe) or in any thread (if dlerror() is not thread-safe).
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
       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 criti-
       cal section to retrieve the error pointer and buffer.
RATIONALE
       None.
FUTURE DIRECTIONS
       None.
SEE ALSO
       dlclose(), dlopen(), dlsym()
       The Base Definitions volume of POSIX.1-2008, <dlfcn.h>
COPYRIGHT
       Portions of this text are reprinted and reproduced in  electronic  form
       from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
       -- Portable Operating System Interface (POSIX),  The  Open  Group  Base
       Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri-
       cal and Electronics Engineers,  Inc  and  The  Open  Group.   (This  is
       POSIX.1-2008  with  the  2013  Technical Corrigendum 1 applied.) 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.unix.org/online.html .
       Any  typographical  or  formatting  errors that appear in this page are
       most likely to have been introduced during the conversion of the source
       files  to  man page format. To report such errors, see https://www.ker-
       nel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group                  2013                          DLERROR(3P)