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fread: segementation fault(coredump) w/o stdlib.h
Post 302286608 by Corona688 on Wednesday 11th of February 2009 02:23:54 PM
02-11-2009
As the doctor would say, "don't do that". 
Either AIX has odd integer sizes, or you're on a 64-bit system. Or perhaps both.
When you use functions that you haven't included headers for, the compiler's forced to guess what parameters the function takes and returns, and will guess they are all integers. This is often a good guess on most 32-bit systems, where int, long, and all pointers are the same size -- 32 bits. But 64-bit systems will have 64-bit pointers while still perhaps having 32-bit integers, causing pointers to get balled up and crammed through the mail slot, so to speak.
Without stdlib.h, the value malloc() gives you is corrupted, causing fread to crash when it uses it.
So, always include the headers! Just because it works 'this time' when you don't doesn't mean it will in all situations.
Either AIX has odd integer sizes, or you're on a 64-bit system. Or perhaps both.When you use functions that you haven't included headers for, the compiler's forced to guess what parameters the function takes and returns, and will guess they are all integers. This is often a good guess on most 32-bit systems, where int, long, and all pointers are the same size -- 32 bits. But 64-bit systems will have 64-bit pointers while still perhaps having 32-bit integers, causing pointers to get balled up and crammed through the mail slot, so to speak.
Without stdlib.h, the value malloc() gives you is corrupted, causing fread to crash when it uses it.
So, always include the headers! Just because it works 'this time' when you don't doesn't mean it will in all situations.
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LEARN ABOUT DEBIAN
explain_ftell_or_die
explain_ftell_or_die(3) Library Functions Manual explain_ftell_or_die(3) NAME
explain_ftell_or_die - get stream position and report errors SYNOPSIS
#include <libexplain/ftell.h> long explain_ftell_or_die(FILE *fp); long explain_ftell_on_error(FILE *fp); DESCRIPTION
The explain_ftell_or_die function is used to call the ftell(3) system call. On failure an explanation will be printed to stderr, obtained from the explain_ftell(3) function, and then the process terminates by calling exit(EXIT_FAILURE). The explain_ftell_on_error function is used to call the ftell(3) system call. On failure an explanation will be printed to stderr, obtained from the explain_ftell(3) function, but still returns to the caller. fp The fp, exactly as to be passed to the ftell(3) system call. RETURN VALUE
The explain_ftell_or_die function only returns on success, see ftell(3) for more information. On failure, prints an explanation and exits, it does not return. The explain_ftell_on_error function always returns the value return by the wrapped ftell(3) system call. EXAMPLE
The explain_ftell_or_die function is intended to be used in a fashion similar to the following example: long result = explain_ftell_or_die(fp); SEE ALSO
ftell(3) get stream position explain_ftell(3) explain ftell(3) errors exit(2) terminate the calling process COPYRIGHT
libexplain version 0.52 Copyright (C) 2010 Peter Miller explain_ftell_or_die(3)