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explain_realloc(3)	    Library Functions Manual	      explain_realloc(3)

NAME
     explain_realloc - explain realloc(3) errors

SYNOPSIS
     #include <libexplain/realloc.h>
     const char *explain_realloc(void *ptr, size_t size);
     const char *explain_errno_realloc(int errnum, void *ptr, size_t size);
     void  explain_message_realloc(char  *message,  int message_size, void *ptr,
     size_t size);
     void explain_message_errno_realloc(char *message, int message_size, int er-
     rnum, void *ptr, size_t size);

DESCRIPTION
     These functions may be used to obtain explanations for errors  returned  by
     the realloc(3) system call.

   explain_realloc
     const char *explain_realloc(void *ptr, size_t size);

     The  explain_realloc  function is used to obtain an explanation of an error
     returned by the realloc(3) system call.  The least the message will contain
     is the value of strerror(errno), but usually it will do  much  better,  and
     indicate the underlying cause in more detail.

     The  errno global variable will be used to obtain the error value to be de-
     coded.

     This function is intended to be used in a fashion similar to the  following
     example:
	    void *new_ptr = realloc(ptr, size);
	    if (!new_ptr)
	    {
		fprintf(stderr, "%s\n", explain_realloc(ptr, size));
		exit(EXIT_FAILURE);
	    }

     The  above  code  example	is  available  pre-packaged as the explain_real-
     loc_or_die(3) function.

     ptr     The original ptr, exactly as passed to the realloc(3) system call.

     size    The original size, exactly as passed to the realloc(3) system call.

     Returns:
	     The message explaining the error.	This message buffer is shared by
	     all libexplain functions which do not supply a buffer in their  ar-
	     gument list.  This will be overwritten by the next call to any lib-
	     explain function which shares this buffer, including other threads.

     Note:  This  function is not thread safe, because it shares a return buffer
     across all threads, and many other functions in this library.

   explain_errno_realloc
     const char *explain_errno_realloc(int errnum, void *ptr, size_t size);

     The explain_errno_realloc function is used to obtain an explanation  of  an
     error  returned  by the realloc(3) system call.  The least the message will
     contain is the value of strerror(errnum), but usually it will do much  bet-
     ter, and indicate the underlying cause in more detail.

     This  function is intended to be used in a fashion similar to the following
     example:
	    void *new_ptr = realloc(ptr, size);
	    if (!new_ptr)
	    {
		int err = errno;
		fprintf(stderr, "%s\n", explain_errno_realloc(err, ptr, size));
		exit(EXIT_FAILURE);
	    }

     The above code example  is  available  pre-packaged  as  the  explain_real-
     loc_or_die(3) function.

     errnum  The  error  value	to  be	decoded, usually obtained from the errno
	     global variable just before this function is called.  This is  nec-
	     essary  if  you need to call any code between the system call to be
	     explained and this function, because many libc functions will alter
	     the value of errno.

     ptr     The original ptr, exactly as passed to the realloc(3) system call.

     size    The original size, exactly as passed to the realloc(3) system call.

     Returns:
	     The message explaining the error.	This message buffer is shared by
	     all libexplain functions which do not supply a buffer in their  ar-
	     gument list.  This will be overwritten by the next call to any lib-
	     explain function which shares this buffer, including other threads.

     Note:  This  function is not thread safe, because it shares a return buffer
     across all threads, and many other functions in this library.

   explain_message_realloc
     void explain_message_realloc(char *message, int  message_size,  void  *ptr,
     size_t size);

     The  explain_message_realloc function may be used to  obtain an explanation
     of an error returned by the realloc(3) system call.  The least the  message
     will  contain  is the value of strerror(errno), but usually it will do much
     better, and indicate the underlying cause in more detail.

     The errno global variable will be used to obtain the error value to be  de-
     coded.

     This  function is intended to be used in a fashion similar to the following
     example:
	    void *new_ptr = realloc(ptr, size);
	    if (!new_ptr)
	    {
		char message[3000];
		explain_message_realloc(message, sizeof(message), ptr, size);
		fprintf(stderr, "%s\n", message);
		exit(EXIT_FAILURE);
	    }

     The above code example  is  available  pre-packaged  as  the  explain_real-
     loc_or_die(3) function.

     message
	     The location in which to store the returned message.  If a suitable
	     message return buffer is supplied, this function is thread safe.

     message_size
	     The  size	in  bytes of the location in which to store the returned
	     message.

     ptr     The original ptr, exactly as passed to the realloc(3) system call.

     size    The original size, exactly as passed to the realloc(3) system call.

   explain_message_errno_realloc
     void explain_message_errno_realloc(char *message, int message_size, int er-
     rnum, void *ptr, size_t size);

     The explain_message_errno_realloc function may be used to obtain an  expla-
     nation  of  an error returned by the realloc(3) system call.  The least the
     message will contain is the value of strerror(errnum), but usually it  will
     do much better, and indicate the underlying cause in more detail.

     This  function is intended to be used in a fashion similar to the following
     example:
	    void *new_ptr = realloc(ptr, size);
	    if (!new_ptr)
	    {
		int err = errno;
		char message[3000];
		explain_message_errno_realloc(message, sizeof(message), err, ptr, size);
		fprintf(stderr, "%s\n", message);
		exit(EXIT_FAILURE);
	    }

     The above code example  is  available  pre-packaged  as  the  explain_real-
     loc_or_die(3) function.

     message
	     The location in which to store the returned message.  If a suitable
	     message return buffer is supplied, this function is thread safe.

     message_size
	     The  size	in  bytes of the location in which to store the returned
	     message.

     errnum  The error value to be decoded,  usually  obtained	from  the  errno
	     global  variable just before this function is called.  This is nec-
	     essary if you need to call any code between the system call  to  be
	     explained and this function, because many libc functions will alter
	     the value of errno.

     ptr     The original ptr, exactly as passed to the realloc(3) system call.

     size    The original size, exactly as passed to the realloc(3) system call.

SEE ALSO
     realloc(3)
	     Allocate and free dynamic memory

     explain_realloc_or_die(3)
	     Allocate and free dynamic memory and report errors

COPYRIGHT
     libexplain version 1.3
     Copyright (C) 2009 Peter Miller

							      explain_realloc(3)

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