dlerror(3p) — Linux manual page

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). The returned pointer might also be
       invalidated if the calling thread is terminated.

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(3p), dlopen(3p), dlsym(3p)

       The Base Definitions volume of POSIX.1‐2017, dlfcn.h(0p)

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic
       form from IEEE Std 1003.1-2017, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The
       Open Group Base Specifications Issue 7, 2018 Edition, Copyright
       (C) 2018 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.opengroup.org/unix/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               2017                       DLERROR(3P)

Pages that refer to this page: dlfcn.h(0p), dlclose(3p), dlopen(3p), dlsym(3p)

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