1DLERROR(3P)                POSIX Programmer's Manual               DLERROR(3P)
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PROLOG

6       This  manual  page is part of the POSIX Programmer's Manual.  The Linux
7       implementation of this interface may differ (consult the  corresponding
8       Linux  manual page for details of Linux behavior), or the interface may
9       not be implemented on Linux.
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NAME

13       dlerror — get diagnostic information
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SYNOPSIS

16       #include <dlfcn.h>
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18       char *dlerror(void);
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DESCRIPTION

21       The dlerror() function shall return a null-terminated character  string
22       (with  no  trailing  <newline>)  that  describes  the  last  error that
23       occurred during dynamic  linking  processing.  If  no  dynamic  linking
24       errors  have occurred since the last invocation of dlerror(), dlerror()
25       shall return NULL.  Thus, invoking dlerror() a second time, immediately
26       following a prior invocation, shall result in NULL being returned.
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28       It  is  implementation-defined whether or not the dlerror() function is
29       thread-safe. A thread-safe implementation shall return only errors that
30       occur on the current thread.
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RETURN VALUE

33       If  successful,  dlerror()  shall  return  a  null-terminated character
34       string; otherwise, NULL shall be returned.
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36       The application shall not modify  the  string  returned.  The  returned
37       pointer might be invalidated or the string content might be overwritten
38       by a subsequent call to dlerror() in the same thread (if  dlerror()  is
39       thread-safe) or in any thread (if dlerror() is not thread-safe).
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ERRORS

42       No errors are defined.
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44       The following sections are informative.
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EXAMPLES

47       The following example prints out the last dynamic linking error:
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49           ...
50           #include <dlfcn.h>
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52           char *errstr;
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54           errstr = dlerror();
55           if (errstr != NULL)
56               printf ("A dynamic linking error occurred: (%s)\n", errstr);
57           ...
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APPLICATION USAGE

60       Depending  on  the application environment with respect to asynchronous
61       execution events, such as signals  or  other  asynchronous  computation
62       sharing  the address space, conforming applications should use a criti‐
63       cal section to retrieve the error pointer and buffer.
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RATIONALE

66       None.
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FUTURE DIRECTIONS

69       None.
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SEE ALSO

72       dlclose(), dlopen(), dlsym()
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74       The Base Definitions volume of POSIX.1‐2008, <dlfcn.h>
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77       Portions of this text are reprinted and reproduced in  electronic  form
78       from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
79       -- Portable Operating System Interface (POSIX),  The  Open  Group  Base
80       Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
81       cal and Electronics Engineers,  Inc  and  The  Open  Group.   (This  is
82       POSIX.1-2008  with  the  2013  Technical Corrigendum 1 applied.) In the
83       event of any discrepancy between this version and the original IEEE and
84       The  Open Group Standard, the original IEEE and The Open Group Standard
85       is the referee document. The original Standard can be  obtained  online
86       at http://www.unix.org/online.html .
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88       Any  typographical  or  formatting  errors that appear in this page are
89       most likely to have been introduced during the conversion of the source
90       files  to  man page format. To report such errors, see https://www.ker‐
91       nel.org/doc/man-pages/reporting_bugs.html .
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95IEEE/The Open Group                  2013                          DLERROR(3P)
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