posix man page for dlerror

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 correspond-
       ing 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)
", 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 Technol-
       ogy -- 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 Stan-
       dard 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 .

IEEE
/The Open Group						       2013							       DLERROR(3P)