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

12       dlerror — get diagnostic information
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SYNOPSIS

15       #include <dlfcn.h>
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17       char *dlerror(void);
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DESCRIPTION

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

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

43       No errors are defined.
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45       The following sections are informative.
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EXAMPLES

48       The following example prints out the last dynamic linking error:
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51           ...
52           #include <dlfcn.h>
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54           char *errstr;
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56           errstr = dlerror();
57           if (errstr != NULL)
58               printf ("A dynamic linking error occurred: (%s)\n", errstr);
59           ...
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APPLICATION USAGE

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

68       None.
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FUTURE DIRECTIONS

71       None.
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SEE ALSO

74       dlclose(), dlopen(), dlsym()
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76       The Base Definitions volume of POSIX.1‐2017, <dlfcn.h>
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79       Portions of this text are reprinted and reproduced in  electronic  form
80       from  IEEE Std 1003.1-2017, Standard for Information Technology -- Por‐
81       table Operating System Interface (POSIX), The Open Group Base  Specifi‐
82       cations  Issue  7, 2018 Edition, Copyright (C) 2018 by the Institute of
83       Electrical and Electronics Engineers, Inc and The Open Group.   In  the
84       event of any discrepancy between this version and the original IEEE and
85       The Open Group Standard, the original IEEE and The Open Group  Standard
86       is  the  referee document. The original Standard can be obtained online
87       at http://www.opengroup.org/unix/online.html .
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89       Any typographical or formatting errors that appear  in  this  page  are
90       most likely to have been introduced during the conversion of the source
91       files to man page format. To report such errors,  see  https://www.ker‐
92       nel.org/doc/man-pages/reporting_bugs.html .
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96IEEE/The Open Group                  2017                          DLERROR(3P)
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