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
       critical 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 Electrical 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.kernel.org/doc/man-pages/reporting_bugs.html .