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Full Discussion: Segmentation fault in fopen when in write mode.
Top Forums Programming Segmentation fault in fopen when in write mode. Post 302673099 by Corona688 on Tuesday 17th of July 2012 12:38:49 PM
Old 07-17-2012
Quote:
Originally Posted by shoaibjameel123
Then I think using size_t or ssize_t would make codes even more portable rather than declaring as int or unsigned int.
Why would you even want to use size_t or ssize_t in main()? It's defined as int. Using fancy defined types isn't the point -- the point of these types isn't to use them everywhere, the point is to use them when you need them. ssize_t is defined to match certain library and system calls, but main() is not among them. You may not realize it, but main() is called by a library which assumes main() is int main(int argc, char *argv[]). Use anything else, and you're lying to that library, feeding it the wrong kind of function. It may work if you're lucky on some platforms where size_t and the like are the right size anyway, but change platforms and it could mess up extravagantly. Segmentation faults, and the like. I've experienced this personally.

In other words -- I think you missed the point of my post.

Are you doing calculations with intentional overflow, bit manipultion, or other such things where -- if your integers aren't 32/64/whatever bits, your code is guaranteed to not work?

These are the sort of circumstances int32_t, uint64_t, et all are designed for.

If you don't actually need 32 bits and nothing but 32 bits, don't demand it.

And never, ever, ever use weird types in things already defined as ordinary types, like in main(). If it works at all it's pure coincidence, and can bite you hard when you go to a radically different architecture or bit width(as I've experienced personally many times. Someone gets overenthusiastic and declares a function as size_t then goes ahead and uses it as int instead somewhere else, causing extremely hard-to-track bugs when parameters getting passed into the function get mangled...)
Last edited by Corona688; 07-17-2012 at 01:46 PM..
This User Gave Thanks to Corona688 For This Post:
shoaibjameel123
 

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LEARN ABOUT SUSE

tk_main

Tk_Main(3)						       Tk Library Procedures							Tk_Main(3)

__________________________________________________________________________________________________________________________________________________

NAME

       Tk_Main - main program for Tk-based applications

SYNOPSIS

       #include <tk.h>

       Tk_Main(argc, argv, appInitProc)

ARGUMENTS

       int argc (in)				  Number of elements in argv.

       char *argv[] (in)			  Array of strings containing command-line arguments.

       Tcl_AppInitProc *appInitProc (in)	  Address  of  an  application-specific  initialization procedure.  The value for this argument is
						  usually Tcl_AppInit.
_________________________________________________________________

DESCRIPTION

       Tk_Main acts as the main program for most Tk-based applications.  Starting with Tk 4.0 it is not called main anymore because it is part	of
       the Tk library and having a function main in a library (particularly a shared library) causes problems on many systems.	Having main in the
       Tk library would also make it hard to use Tk in C++ programs, since C++ programs must have special C++ main functions.

       Normally each application contains a small main function that does nothing but invoke Tk_Main.  Tk_Main then does all the work of  creating
       and running a wish-like application.

       When  it  is  has  finished  its own initialization, but before it processes commands, Tk_Main calls the procedure given by the appInitProc
       argument.  This procedure provides a "hook" for the application to perform its own initialization, such	as  defining  application-specific
       commands.  The procedure must have an interface that matches the type Tcl_AppInitProc:
	      typedef int Tcl_AppInitProc(Tcl_Interp *interp);
       AppInitProc is almost always a pointer to Tcl_AppInit; for more details on this procedure, see the documentation for Tcl_AppInit.

KEYWORDS

       application-specific initialization, command-line arguments, main program

Tk									4.0								Tk_Main(3)
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