Re: So how do you know which lib goes with a header file (dumb question I know)
On Mar 26, 11:15 pm, Brian Keener
<bkeenerReMoVeAnTiS...@thesoftwaresource.com> wrote:
From other posts I have made I have made I have been told the
only way to know what is in which header files is to look and
as you learn the headers you will know what is available.
Even some of the books I have read say the header is the
programmers explanation/interface to the various tasks he
might need to perform for a particular class or task.
I don't know who's been saying that, but it is completely wrong.
As a programmer, you really should never look in header file
you're not called on to maintain. Header files are NOT program
documentation. (Some libraries do generate documentation from
header files, e.g. with Doxygen or such. Which is really going
about things backwards, but you don't always have the tools you
need to do it correctly. The preferred procedure, of course, is
to write the documentation first, and use it to generate the
header.)
But..... once you find a header (whether in be a standard C++
or some addon header) how do you know which Library you need
to use. I guess I am really asking about the standards since
if it is some addon there might be examples and documentation
so let's limit this to the standards.
The same place you find out which functions and classes are
available: the documentation. I'm not sure about other systems,
and not all third party libraries obey the convention either,
but under Unix, it is customary for the man page to contain a
synopsis, at the very top, which includes:
-- an example of how to invoke the compiler when using the
function (if necessary---it's not present if no particular
options or non-default libraries are present),
-- the include statements needed at the top of the program, and
-- the syntax of the function---roughly, the external
declaration of the function.
Thus, for something like pthread_create, the man page starts
something like:
NAME
pthread_create - create a thread
SYNOPSIS
cc -mt [ flag... ] file...- lpthread [ library... ]
#include <pthread.h>
int pthread_create(pthread_t *thread, const pthread_attr_t
*attr, void *(*start_routine, void*),void *arg);
Not that Unix documentation is particularly good, but it does
establish a minimum. And I'm pretty sure that the situation is
similar under Windows (except that the Windows system
documentation is a little bit better organized); I recently
ported a significant bit of system dependant code to Windows,
and I found all the information I needed in the documentation.
This mainly concerns the system level documentation, of course,
but it does establish a standard; I would expect any third party
libraries to conform to the conventions of the local system.
--
James Kanze (GABI Software) mailto:james.kanze@gmail.com
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