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explain_malloc(3)	   Library Functions Manual	     explain_malloc(3)

NAME
       explain_malloc -	explain	malloc(3) errors

SYNOPSIS
       #include	<libexplain/malloc.h>
       const char *explain_malloc(size_t size);
       const char *explain_errno_malloc(int errnum, size_t size);
       void  explain_message_malloc(char  *message,  int  message_size,	size_t
       size);
       void explain_message_errno_malloc(char *message,	int message_size,  int
       errnum, size_t size);

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

   explain_malloc
       const char *explain_malloc(size_t size);

       The explain_malloc function is used to obtain an	explanation of an  er-
       ror  returned by	the malloc(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
       decoded.

       This function is	intended to be used in a fashion similar to  the  fol-
       lowing example:
	      if (malloc(size) < 0)
	      {
		  fprintf(stderr, "%s\n", explain_malloc(size));
		  exit(EXIT_FAILURE);
	      }

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

       size    The original size, exactly as passed to	the  malloc(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  argument list.  This will be overwritten by the next
	       call to any libexplain function which shares this  buffer,  in-
	       cluding other threads.

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

   explain_errno_malloc
       const char *explain_errno_malloc(int errnum, size_t size);

       The explain_errno_malloc	function is used to obtain an  explanation  of
       an  error returned by the malloc(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 fol-
       lowing example:
	      if (malloc(size) < 0)
	      {
		  int err = errno;
		  fprintf(stderr, "%s\n", explain_errno_malloc(err, size));
		  exit(EXIT_FAILURE);
	      }

       The above code example is available pre-packaged	 as  the  explain_mal-
       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
	       necessary  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.

       size    The  original  size,  exactly as	passed to the malloc(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	argument list.	This will be overwritten by  the  next
	       call  to	 any libexplain	function which shares this buffer, in-
	       cluding other threads.

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

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

       The explain_message_malloc function may be used to  obtain an  explana-
       tion  of	an error returned by the malloc(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
       decoded.

       This function is	intended to be used in a fashion similar to  the  fol-
       lowing example:
	      if (malloc(size) < 0)
	      {
		  char message[3000];
		  explain_message_malloc(message, sizeof(message), size);
		  fprintf(stderr, "%s\n", message);
		  exit(EXIT_FAILURE);
	      }

       The  above  code	 example is available pre-packaged as the explain_mal-
       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  re-
	       turned message.

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

   explain_message_errno_malloc
       void explain_message_errno_malloc(char *message,	int message_size,  int
       errnum, size_t size);

       The  explain_message_errno_malloc function may be used to obtain	an ex-
       planation of an error returned by the malloc(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  de-
       tail.

       This  function  is intended to be used in a fashion similar to the fol-
       lowing example:
	      if (malloc(size) < 0)
	      {
		  int err = errno;
		  char message[3000];
		  explain_message_errno_malloc(message,	sizeof(message), err, size);
		  fprintf(stderr, "%s\n", message);
		  exit(EXIT_FAILURE);
	      }

       The above code example is available pre-packaged	 as  the  explain_mal-
       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 re-
	       turned message.

       errnum  The error value to be decoded, usually obtained from the	 errno
	       global  variable	 just before this function is called.  This is
	       necessary 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.

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

SEE ALSO
       malloc(3)
	       Allocate	and free dynamic memory

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

COPYRIGHT
       libexplain version 1.3
       Copyright (C) 2009 Peter	Miller

							     explain_malloc(3)

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | COPYRIGHT

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