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

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       The  dlerror()  function  need not be reentrant. A function that is not
29       required to be reentrant is not required to be thread-safe.
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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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ERRORS

36       No errors are defined.
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38       The following sections are informative.
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EXAMPLES

41       The following example prints out the last dynamic linking error:
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44              ...
45              #include <dlfcn.h>
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48              char *errstr;
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51              errstr = dlerror();
52              if (errstr != NULL)
53              printf ("A dynamic linking error occurred: (%s)\n", errstr);
54              ...
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APPLICATION USAGE

57       The  messages  returned by dlerror() may reside in a static buffer that
58       is overwritten on each call to dlerror().  Application code should  not
59       write  to  this  buffer.  Programs wishing to preserve an error message
60       should make their own copies of that message. Depending on the applica‐
61       tion environment with respect to asynchronous execution events, such as
62       signals or other asynchronous computation sharing  the  address  space,
63       conforming  applications  should use a critical section to retrieve the
64       error pointer and buffer.
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RATIONALE

67       None.
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FUTURE DIRECTIONS

70       None.
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SEE ALSO

73       dlclose(),  dlopen(),  dlsym(),  the   Base   Definitions   volume   of
74       IEEE Std 1003.1-2001, <dlfcn.h>
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77       Portions  of  this text are reprinted and reproduced in electronic form
78       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
79       --  Portable  Operating  System  Interface (POSIX), The Open Group Base
80       Specifications Issue 6, Copyright (C) 2001-2003  by  the  Institute  of
81       Electrical  and  Electronics  Engineers, Inc and The Open Group. In the
82       event of any discrepancy between this version and the original IEEE and
83       The  Open Group Standard, the original IEEE and The Open Group Standard
84       is the referee document. The original Standard can be  obtained  online
85       at http://www.opengroup.org/unix/online.html .
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89IEEE/The Open Group                  2003                          DLERROR(3P)
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