Provided by: libexplain-dev_1.4.D001-12_amd64 bug

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 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 following 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_malloc_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,
               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_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 following 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_malloc_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,
               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_malloc
       void explain_message_malloc(char *message, int message_size, size_t size);

       The explain_message_malloc function may be 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(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 following 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_malloc_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.

       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 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 following 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_malloc_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 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 1.4
       Copyright (C) 2009 Peter Miller

                                                                                explain_malloc(3)