This is mikmod.info, produced by makeinfo version 4.13 from mikmod.texi.

Copyright (C) 1998-2014 Miodrag Vallat and others -- see file AUTHORS

for complete list.

This library is free software; you can redistribute it and/or modify

it under the terms of the GNU Library General Public License as

published by the Free Software Foundation; either version 2 of the

License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but

WITHOUT ANY WARRANTY; without even the implied warranty of

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Library General Public License for more details.

You should have received a copy of the GNU Library General Public

License along with this library; if not, write to the Free Software

Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,

USA.

INFO-DIR-SECTION Programming

START-INFO-DIR-ENTRY

* MikMod: (mikmod). MikMod Sound Library.

END-INFO-DIR-ENTRY



File: mikmod.info, Node: Top, Next: Introduction, Prev: (dir), Up: (dir)

MikMod Sound Library

********************

This manual documents the MikMod Sound Library, version 3.1.21.

* Menu:

* Introduction:: What is MikMod ?

* Tutorial:: Your first steps with MikMod.

* Using the Library:: A thematic presentation of the library.

* Library Reference:: Detailed description of the functions and variables.

* Index::



File: mikmod.info, Node: Introduction, Next: Tutorial, Prev: Top, Up: Top

1 Introduction

**************

The MikMod sound library is an excellent way for a programmer to add

music and sound effects to an application. It is a powerful and

flexible library, with a simple and easy-to-learn API.

Besides, the library is very portable and runs under a lot of

Unices, as well as under OS/2, MacOS and Windows. Third party

individuals also maintain ports on other systems, including MS-DOS, and

BeOS.

MikMod is able to play a wide range of module formats, as well as

digital sound files. It can take advantage of particular features of

your system, such as sound redirection over the network. And due to its

modular nature, the library can be extended to support more sound or

module formats, as well as new hardware or other sound output

capabilities, as they appear.



File: mikmod.info, Node: Tutorial, Next: Using the Library, Prev: Introduction, Up: Top

2 Tutorial

**********

This chapter will describe how to quickly incorporate MikMod's power

into your programs. It doesn't cover everything, but that's a start and

I hope it will help you understand the library philosophy.

If you have a real tutorial to put here, you're welcome ! Please

send it to me...

* Menu:

* MikMod Concepts:: A few things you'll need to know.

* A Skeleton Program:: The shortest MikMod program.

* Playing Modules:: How to create a simple module player.

* Playing Sound Effects:: How to play simple sound effects.

* More Sound Effects:: How to play more complex sound effects.



File: mikmod.info, Node: MikMod Concepts, Next: A Skeleton Program, Prev: Tutorial, Up: Tutorial

2.1 MikMod Concepts

===================

MikMod's sound output is composed of several sound _voices_ which are

mixed, either in software or in hardware, depending of your hardware

configuration. Simple sounds, like sound effects, use only one voice,

whereas sound modules, which are complex arrangements of sound effects,

use several voices.

MikMod's functions operate either globally, or at the voice level.

Differences in the handling of sound effects and modules are kept

minimal, at least for the programmer.

The sound playback is done by a _sound driver_. MikMod provides

several sound drivers: different hardware drivers, and some software

drivers to redirect sound in a file, or over the network. You can even

add your own driver, register it to make it known by the library, and

select it (this is exactly what the module plugin of xmms does).



File: mikmod.info, Node: A Skeleton Program, Next: Playing Modules, Prev: MikMod Concepts, Up: Tutorial

2.2 A Skeleton Program

======================

To use MikMod in your program, there are a few steps required:

* Include `mikmod.h' in your program.

* Register the MikMod drivers you need.

* Initialize the library with MikMod_Init() before using any other

MikMod function.

* Give up resources with MikMod_Exit() at the end of your program,

or before when MikMod is not needed anymore.

* Link your application with the MikMod sound library.

Here's a program which meets all those conditions:

/* MikMod Sound Library example program: a skeleton */

#include <mikmod.h>

main()

{

/* register all the drivers */

MikMod_RegisterAllDrivers();

/* initialize the library */

MikMod_Init("");

/* we could play some sound here... */

/* give up */

MikMod_Exit();

}

This program would be compiled with the following command line: `cc

-o example example.c `libmikmod-config --cflags` `libmikmod-config

--libs`'

Although this programs produces no useful result, many things happen

when you run it. The call to `MikMod_RegisterAllDrivers' registers all

the drivers embedded in the MikMod library. Then, `MikMod_Init' chooses

the more adequate driver and initializes it. The program is now ready

to produce sound. When sound is not needed any more, `MikMod_Exit' is

used to relinquish memory and let other programs have access to the

sound hardware.



File: mikmod.info, Node: Playing Modules, Next: Playing Sound Effects, Prev: A Skeleton Program, Up: Tutorial

2.3 Playing Modules

===================

Our program is not really useful if it doesn't produce sound. Let's

suppose you've got this good old module, "Beyond music", in the file

`beyond music.mod'. How about playing it ?

To do this, we'll use the following code:

/* MikMod Sound Library example program: a simple module player */

#include <unistd.h>

#include <mikmod.h>

main()

{

MODULE *module;

/* register all the drivers */

MikMod_RegisterAllDrivers();

/* register all the module loaders */

MikMod_RegisterAllLoaders();

/* initialize the library */

md_mode |= DMODE_SOFT_MUSIC;

if (MikMod_Init("")) {

fprintf(stderr, "Could not initialize sound, reason: %s\n",

MikMod_strerror(MikMod_errno));

return;

}

/* load module */

module = Player_Load("beyond music.mod", 64, 0);

if (module) {

/* start module */

Player_Start(module);

while (Player_Active()) {

/* we're playing */

usleep(10000);

MikMod_Update();

}

Player_Stop();

Player_Free(module);

} else

fprintf(stderr, "Could not load module, reason: %s\n",

MikMod_strerror(MikMod_errno));

/* give up */

MikMod_Exit();

}

What's new here ? First, we've not only registered MikMod's device

driver, but also the module loaders. MikMod comes with a large choice

of module loaders, each one for a different module type. Since _every_

loader is called to determine the type of the module when we try to

load them, you may want to register only a few of them to save time. In

our case, we don't matter, so we happily register every module loader.

Then, there's an extra line before calling `MikMod_Init'. We change

the value of MikMod's variable `md_mode' to tell the library that we

want the module to be processed by the software. If you're the happy

owner of a GUS-type card, you could use the specific hardware driver

for this card, but in this case you should not set the

`DMODE_SOFT_MUSIC' flag.

We'll ensure that `MikMod_Init' was successful. Note that, in case of

error, MikMod provides the variable `MikMod_errno', an equivalent of

the C library `errno' for MikMod errors, and the function

`MikMod_strerror', an equivalent to `strerror'.

Now onto serious business ! The module is loaded with the

`Player_Load' function, which takes the name of the module file, and

the number of voices afforded to the module. In this case, the module

has only 4 channels, so 4 voices, but complex Impulse Tracker modules

can have a lot of voices (as they can have as many as 256 virtual

channels with so-called "new note actions"). Since empty voices don't

cost time to be processed, it is safe to use a big value, such as 64 or

128. The third parameter is the "curiosity" of the loader: if nonzero,

the loader will search for hidden parts in the module. However, only a

few module formats can embed hidden or non played parts, so we'll use 0

here.

Now that the module is ready to play, let's play it. We inform the

player that the current module is `module' with `Player_Start'.

Playback starts, but we have to update it on a regular basis. So

there's a loop on the result of the `Player_Active' function, which

will tell us if the module has finished. To update the sound, we simply

call `MikMod_Update'.

After the module has finished, we tell the player its job is done

with `Player_Stop', and we free the module with `Player_Free'.



File: mikmod.info, Node: Playing Sound Effects, Next: More Sound Effects, Prev: Playing Modules, Up: Tutorial

2.4 Playing Sound Effects

=========================

MikMod is not limited to playing modules, it can also play sound

effects, that is, module samples. It's a bit more complex than playing

a module, because the module player does a lot of things for us, but

here we'll get more control over what is actually played by the

program. Let's look at an example:

/* MikMod Sound Library example program: sound effects */

#include <unistd.h>

#include <mikmod.h>

main()

{

int i;

/* sound effects */

SAMPLE *sfx1, *sfx2;

/* voices */

int v1, v2;

/* register all the drivers */

MikMod_RegisterAllDrivers();

/* initialize the library */

md_mode |= DMODE_SOFT_SNDFX;

if (MikMod_Init("")) {

fprintf(stderr, "Could not initialize sound, reason: %s\n",

MikMod_strerror(MikMod_errno));

return;

}

/* load samples */

sfx1 = Sample_Load("first.wav");

if (!sfx1) {

MikMod_Exit();

fprintf(stderr, "Could not load the first sound, reason: %s\n",

MikMod_strerror(MikMod_errno));

return;

}

sfx2 = Sample_Load("second.wav");

if (!sfx2) {

Sample_Free(sfx1);

MikMod_Exit();

fprintf(stderr, "Could not load the second sound, reason: %s\n",

MikMod_strerror(MikMod_errno));

return;

}

/* reserve 2 voices for sound effects */

MikMod_SetNumVoices(-1, 2);

/* get ready to play */

MikMod_EnableOutput();

/* play first sample */

v1 = Sample_Play(sfx1, 0, 0);

for(i = 0; i < 5; i++) {

MikMod_Update();

usleep(100000);

}

/* half a second later, play second sample */

v2 = Sample_Play(sfx2, 0, 0);

do {

MikMod_Update();

usleep(100000);

} while (!Voice_Stopped(v2));

MikMod_DisableOutput();

Sample_Free(sfx2);

Sample_Free(sfx1);

MikMod_Exit();

}

As in the previous example, we begin by registering the sound

drivers and initializing the library. We also ask for software mixing

by modifying the variable `md_mode'.

It's time to load our files, with the `Sample_Load' function. Don't

forget to test the return value -- it looks ugly here on such a small

example, but it's a good practice...

Since we want to play two samples, we have to use at least two

voices for this, so we reserve them with a `MikMod_SetNumVoices' call.

The first parameter sets the number of module voices, and the second

parameter the number of sound effect voices. We don't want to set the

number of module voices here (it's part of the module player's duty),

so we use the value `-1' to keep the current value, and we reserve two

sound effect voices.

Now we're ready to play, so we call `MikMod_EnableOutput' to make the

driver ready. Sound effects are played by the `Sample_Play' function.

You just have to specify which sample you want to play, the offset from

which you want to start, and the playback flags. More on this later.

The function returns the number of the voice associated to the sample.

We play the first sample for half a second, then we start to play

the second sample. Since we've reserved two channels, both samples play

simultaneously. We use the `Voice_Stopped' function to stop the

playback: it returns the current status of the voice argument, which is

zero when the sample plays and nonzero when it has finished. So the

`do' loop will stop exactly when the second sample is finished,

regardless of the length of the first sample.

To finish, we get rid of the samples with `Sample_Free'.



File: mikmod.info, Node: More Sound Effects, Prev: Playing Sound Effects, Up: Tutorial

2.5 More Sound Effects

======================

Sound effects have some attributes that can be affected to control the

playback. These are speed, panning, and volume. Given a voice number,

you can affect these attributes with the `Voice_SetFrequency',

`Voice_SetPanning' and `Voice_SetVolume' functions.

In the previous example, we'll replace the actual sound code,

located between the calls to `MikMod_EnableOutput' and

`MikMod_DisableOutput', with the following code:

Sample_Play(sfx1, 0, 0);

for(i = 0; i < 5; i++) {

MikMod_Update();

usleep(100000);

}

v2 = Sample_Play(sfx2, 0, SFX_CRITICAL);

i = 0;

do {

MikMod_Update();

usleep(100000);

v1 = Sample_Play(sfx1, 0, 0);

Voice_SetVolume(v1, 160);

Voice_SetFrequency(v1, (sfx1->speed * (100 + i)) / 100);

Voice_SetPanning(v2, (i++ & 1) ? PAN_LEFT : PAN_RIGHT);

} while (!Voice_Stopped(v2));

The first thing you'll notice, is the `SFX_CRITICAL' flag used to

play the second sample. Since the `do' loop will add another sample

every 100 milliseconds, and we reserved only two voices, the oldest

voice will be cut each time this is necessary. Doing this would cut the

second sample in the second iteration of the loop. However, since we

flagged this sound as "critical", it won't be cut until it is finished

or we stop it with a `Voice_Stop' call. So the second sample will play

fine, whereas the first sample will be stopped every loop iteration.

Then, we choose to play the first sample a bit lower, with

`Voice_SetVolume'. Volume voices range from 0 (silence) to 256. In this

case we play the sample at 160. To make the sound look weird, we also

change its frequency with `Voice_SetFrequency'. The computation in the

example code makes the frequency more and more high (starting from the

sample frequency and then increasing from 1% each iteration).

And to demonstrate the `Voice_SetPanning' function, we change the

panning of the second sample at each iteration from the left to the

right. The argument can be one of the standard panning `PAN_LEFT',

`PAN_RIGHT', `PAN_CENTER' and `PAN_SURROUND'(1), or a numeric value

between 0 (`PAN_LEFT') and 255 (`PAN_RIGHT').

---------- Footnotes ----------

(1) `PAN_SURROUND' will be mapped to `PAN_CENTER' if the library is

initialized without surround sound, that is, if the variable `md_mode'

doesn't have the bit `DMODE_SURROUND' set.



File: mikmod.info, Node: Using the Library, Next: Library Reference, Prev: Tutorial, Up: Top

3 Using the Library

*******************

This chapter describes the various parts of the library and their uses.

* Menu:

* Library Version::

* Type Definitions::

* Error Handling::

* Library Initialization::

* Samples and Voice Control::

* Modules and Player Control::

* Loading Data from Memory::



File: mikmod.info, Node: Library Version, Next: Type Definitions, Prev: Using the Library, Up: Using the Library

3.1 Library Version

===================

If your program is dynamically linked with the MikMod library, you

should check which version of the library you're working with. To do

this, the library defines a few constants and a function to help you

determine if the current library is adequate for your needs or if it

has to be upgraded.

When your program includes `mikmod.h', the following constants are

defined:

* `LIBMIKMOD_VERSION_MAJOR' is equal to the major version number of

the library.

* `LIBMIKMOD_VERSION_MINOR' is equal to the minor version number of

the library.

* `LIBMIKMOD_REVISION' is equal to the revision number of the

library.

* `LIBMIKMOD_VERSION' is the sum of `LIBMIKMOD_VERSION_MAJOR'

shifted 16 times, `LIBMIKMOD_VERSION_MINOR' shifted 8 times, and

`LIBMIKMOD_REVISION'.

So your program can tell with which version of the library it has

been compiled this way:

printf("Compiled with MikMod Sound Library version %ld.%ld.%ld\n",

LIBMIKMOD_VERSION_MAJOR,

LIBMIKMOD_VERSION_MINOR,

LIBMIKMOD_REVISION);

The library defines the function `MikMod_GetVersion' which returns

the value of LIBMIKMOD_VERSION for the library. If this value is

greater than or equal to the value of LIBMIKMOD_VERSION for your

program, your program will work; otherwise, you'll have to inform the

user that he has to upgrade the library:

{

long engineversion = MikMod_GetVersion();

if (engineversion < LIBMIKMOD_VERSION) {

printf("MikMod library version (%ld.%ld.%ld) is too old.\n",

(engineversion >> 16) & 255,

(engineversion >> 8) & 255,

(engineversion) & 255);

printf("This programs requires at least version %ld.%ld.%ld\n",

LIBMIKMOD_VERSION_MAJOR,

LIBMIKMOD_VERSION_MINOR,

LIBMIKMOD_REVISION);

puts("Please upgrade your MikMod library.");

exit(1);

}

}



File: mikmod.info, Node: Type Definitions, Next: Error Handling, Prev: Library Version, Up: Using the Library

3.2 Type Definitions

====================

MikMod defines several data types to deal with modules and sample data.

These types have the same memory size on every platform MikMod has been

ported to.

These types are:

* `CHAR' is a printable character. For now it is the same as the

`char' type, but in the future it may be wide char (Unicode) on

some platforms.

* `SBYTE' is a signed 8 bit number (can range from -128 to 127).

* `UBYTE' is an unsigned 8 bit number (can range from 0 to 255).

* `SWORD' is a signed 16 bit number (can range from -32768 to 32767).

* `UWORD' is an unsigned 16 bit number (can range from 0 to 65535).

* `SLONG' is a signed 32 bit number (can range from -2.147.483.648 to

2.147.483.647).

* `ULONG' is an unsigned 32 bit number (can range from 0 to

4.294.967.296).

* `BOOL' is a boolean value. A value of 0 means false, any other

value means true.



File: mikmod.info, Node: Error Handling, Next: Library Initialization, Prev: Type Definitions, Up: Using the Library

3.3 Error Handling

==================

Although MikMod does its best to do its work, there are times where it

can't. For example, if you're trying to play a corrupted file, well,

it can't.

A lot of MikMod functions return pointers or `BOOL' values. If the

pointer is `NULL' or the `BOOL' is 0 (false), an error has occurred.

MikMod errors are returned in the variable `MikMod_errno'. Each

possible error has a symbolic error code, beginning with `MMERR_'. For

example, if MikMod can't open a file, `MikMod_errno' will receive the

value `MMERR_OPENING_FILE'.

You can get an appropriate error message to display from the function

`MikMod_strerror'.

There is a second error variable named `MikMod_critical'. As its name

suggests, it is only set if the error lets the library in an unstable

state. This variable can only be set by the functions `MikMod_Init',

`MikMod_SetNumVoices' and `MikMod_EnableOutput'. If one of these

functions return an error and `MikMod_critical' is set, the library is

left in the uninitialized state (i.e. it was not initialized, or

`MikMod_Exit' was called).

If you prefer, you can use a callback function to get notified of

errors. This function must be prototyped as `void MyFunction(void)'.

Then, call `MikMod_RegisterHandler' with your function as argument to

have it notified when an error occurs. There can only be one callback

function registered, but `MikMod_RegisterHandler' will return you the

previous handler, so you can chain handlers if you want to.



File: mikmod.info, Node: Library Initialization, Next: Samples and Voice Control, Prev: Error Handling, Up: Using the Library

3.4 Library Initialization and Core Functions

=============================================

To initialize the library, you must register some sound drivers first.

You can either register all the drivers embedded in the library for

your platform with `MikMod_RegisterAllDrivers', or register only some

of them with `MikMod_RegisterDriver'. If you choose to register the

drivers manually, you must be careful in their order, since

`MikMod_Init' will try them in the order you registered them. The

`MikMod_RegisterAllDrivers' function registers the network drivers

first (for playing sound over the network), then the hardware drivers,

then the disk writers, and in last resort, the nosound driver.

Registering the nosound driver first would not be a very good idea...

You can get some printable information regarding the registered

drivers with `MikMod_InfoDriver'; don't forget to call `free' on the

returned string when you don't need it anymore.

After you've registered your drivers, you can initialize the sound

playback with `MikMod_Init', passing specific information to the driver

if necessary. If you set the variable `md_device' to zero, which is its

default value, the driver will be autodetected, that is, the first

driver in the list that is available on the system will be used;

otherwise only the driver whose order in the list of the registered

drivers is equal to `md_device' will be tried. If your playback

settings, in the variables `md_mixfreq' and `md_mode', are not

supported by the device, `MikMod_Init' will fail.

You can then choose the number of voices you need with

`MikMod_SetNumVoices', and activate the playback with

`MikMod_EnableOutput'.

Don't forget to call `MikMod_Update' as often as possible to process

the sound mixing. If necessary, fork a dedicated process to do this, or

if the library is thread-safe on your system, use a dedicated thread.

If you want to change playback settings, most of them can't be

changed on the fly. You'll need to stop the playback and reinitialize

the driver. Use `MikMod_Active' to check if there is still sound

playing; in this case, call `MikMod_DisableOutput' to end playback.

Then, change your settings and call `MikMod_Reset'. You're now ready to

select your number of voices and restart playback.

When your program ends, don't forget to stop playback and call

`MikMod_Exit' to leave the sound hardware in a coherent state.

On systems that have pthreads, libmikmod is thread-safe(1). You can

check this in your programs with the `MikMod_InitThreads' function. If

this function returns 1, the library is thread-safe.

The main benefit of thread-safety is that `MikMod_Update' can be

called from a separate thread, which often makes application design

easier. However, several libmikmod global variables are accessible from

all your threads, so when more than one thread need to access libmikmod

variables, you'll have to protect these access with the `MikMod_Lock'

and `MikMod_Unlock' functions. If libmikmod is not thread-safe, these

functions are no-ops.

---------- Footnotes ----------

(1) Unless you explicitely choose to create a non thread-safe

version of libmikmod at compile-time.



File: mikmod.info, Node: Samples and Voice Control, Next: Modules and Player Control, Prev: Library Initialization, Up: Using the Library

3.5 Samples and Voice Control

=============================

Currently, MikMod only supports uncompressed mono WAV files as samples.

You can load a sample by calling `Sample_Load' with a filename, or by

calling `Sample_LoadFP' with an open `FILE*' pointer. These functions

return a pointer to a `SAMPLE' structure, or `NULL' in case of error.

The `SAMPLE' structure has a few interesting fields:

- `speed' contains the default frequency of the sample.

- `volume' contains the default volume of the sample, ranging from 0

(silence) to 64.

- `panning' contains the default panning position of the sample.

Altering one of those fields will affect all voices currently

playing the sample. You can achieve the same result on a single voice

with the functions `Voice_SetFrequency', `Voice_SetVolume' and

`Voice_SetPanning'. Since the same sample can be played with different

frequency, volume and panning parameters on each voice, you can get

voice specific information with `Voice_GetFrequency', `Voice_GetVolume'

and `Voice_GetPanning'.

You can also make your sample loop by setting the fields `loopstart'

and `loopend' and or'ing `flags' with `SF_LOOP'. To compute your loop

values, the field `length' will be useful. However, you must know that

all the sample length are expressed in samples, i.e. 8 bits for an 8

bit sample, and 16 bit for a 16 bit sample... Test `flags' for the value

`SF_16BITS' to know this.

Speaking of flags, if you're curious and want to know the original

format of the sample on disk (since libmikmod does some work on the

sample data internally), refer to the `inflags' field.

If the common forward loop isn't enough, you can play with some

other flags: `SF_BIDI' will make your sample loop "ping pong" (back and

forth), and `SF_REVERSE' will make it play backwards.

To play your sample, use the `Sample_Play' function. This function

will return a voice number which enable you to use the `Voice_xx'

functions.

The sample will play until another sample takes over its voice (when

you play more samples than you reserved sound effect voices), unless it

has been flagged as `SFX_CRITICAL'. You can force it to stop with

`Voice_Stop', or you can force another sample to take over this voice

with `Voice_Play'; however `Voice_Play' doesn't let you flag the new

sample as critical.

Non looping samples will free their voice channel as soon as they

are finished; you can know the current playback position of your sample

with `Voice_GetPosition'. If it is zero, either the sample has finished

playing or it is just beginning; use `Voice_Stopped' to know.

When you don't need a sample anymore, don't forget to free its

memory with `Sample_Free'.



File: mikmod.info, Node: Modules and Player Control, Next: Loading Data from Memory, Prev: Samples and Voice Control, Up: Using the Library

3.6 Modules and Player Control

==============================

As for the sound drivers, you have to register the module loaders you

want to use for MikMod to be able to load modules. You can either

register all the module loaders with `MikMod_RegisterAllLoaders', or

only a few of them with `MikMod_RegisterLoader'. Be careful if you

choose this solution, as the 15 instrument MOD loader has to be

registered last, since loaders are called in the order they were

register to identify modules, and the detection of this format is not

fully reliable, so other modules might be mistaken as 15 instrument MOD

files.

You can get some printable information regarding the registered

loaders with `MikMod_InfoLoader'; don't forget to call `free' on the

returned string when you don't need it anymore.

Note that, contrary to the sound drivers, you can register module

loaders at any time, it doesn't matter.

For playlists, you might be interested in knowing the module title

first, and `Player_LoadTitle' will give you this information. Don't

forget to `free' the returned text when you don't need it anymore.

You can load a module either with `Player_Load' and the name of the

module, or with `Player_LoadFP' and an open `FILE*' pointer. These

functions also expect a maximal number of voices, and a curiosity flag.

Unless you have excellent reasons not to do so, choose a big limit,

such as 64 or even 128 for complex Impulse Tracker modules. Both

functions return a pointer to an `MODULE' structure, or `NULL' if an

error occurs.

You'll find some useful information in this structure:

- `numchn' contains the number of module "real" channels.

- `numvoices' contains the number of voices reserved by the player

for the real channels and the virtual channels (NNA).

- `numpas' and `numpat' contain the number of song positions and

song patterns.

- `numins' and `numsmp' contain the number of instruments and

samples.

- `songname' contains the song title.

- `modtype' contains the name of the tracker used to create the song.

- `comment' contains the song comment, if it has one.

- `sngtime' contains the time elapsed in the module, in 2^-10

seconds (not exactly a millisecond).

- `sngspd' and `bpm' contain the song speed and tempo.

- `realchn' contains the actual number of active channels.

- `totalchn' contains the actual number of active virtual channels,

i.e. the sum of `realchn' and the number of NNA virtual channels.

Now that the module is loaded, you need to tell the module player

that you want to play this particular module with `Player_Start' (the

player can only play one module, but you can have several modules in

memory). The playback begins. Should you forget which module is

playing, `Player_GetModule' will return it to you.

You can change the current song position with the functions

`Player_NextPosition', `Player_PrevPosition' and `Player_SetPosition',

the speed with `Player_SetSpeed' and `Player_SetTempo', and the volume

(ranging from 0 to 128) with `Player_SetVolume'.

Playback can be paused or resumed with `Player_TogglePause'. Be sure

to check with `Player_Paused' that it isn't already in the state you

want !

Fine player control is achieved by the functions `Player_Mute',

`Player_UnMute' and `Player_ToggleMute' which can silence or resume a

set of module channels. The function `Player_Muted' will return the

state of a given channel. And if you want even more control, you can

get the voice corresponding to a module channel with

`Player_GetChannelVoice' and act directly on the voice.

Modules play only once, but can loop indefinitely if they are

designed to do so. You can change this behavior with the `wrap' and

`loop' of the `MODULE' structure; the first one, if set, will make the

module restart when it's finished, and the second one, if set, will

prevent the module from jumping backwards.

You can test if the module is still playing with `Player_Active',

and you can stop it at any time with `Player_Stop'. When the module

isn't needed anymore, get rid of it with `Player_Free'.



File: mikmod.info, Node: Loading Data from Memory, Prev: Modules and Player Control, Up: Using the Library

3.7 Loading Data from Memory

============================

If you need to load modules or sound effects from other places than

plain files, you can use the `MREADER' and `MWRITER' objects to achieve

this.

The `MREADER' and `MWRITER' structures contain a list of function

pointers, which emulate the behaviour of a regular `FILE *' object. In

fact, all functions which take filenames or `FILE *' as arguments are

only wrappers to a real function which takes an `MREADER' or an

`MWRITER' argument.

So, if you need to load a module from memory, or for a multi-file

archive, for example, all you need is to build an adequate `MREADER'

object, and use `Player_LoadGeneric' instead of `Player_Load' or

`Player_LoadFP'. For samples, use `Sample_LoadGeneric' instead of

`Sample_Load' or `Sample_LoadFP'.



File: mikmod.info, Node: Library Reference, Next: Index, Prev: Using the Library, Up: Top

4 Library Reference

*******************

This chapter describes in more detail all the functions and variables

provided by the library. *Note Type Definitions::, for the basic type

reference.

* Menu:

* Variable Reference::

* Structure Reference::

* Error Reference::

* Function Reference::

* Loader Reference::

* Driver Reference::



File: mikmod.info, Node: Variable Reference, Next: Structure Reference, Prev: Library Reference, Up: Library Reference

4.1 Variable Reference

======================

4.1.1 Error Variables

---------------------

The following variables are set by the library to return error

information.

`int MikMod_errno'

When an error occurs, this variable contains the error code.

*Note Error Reference::, for more information.

`BOOL MikMod_critical'

When an error occurs, this variable informs of the severity of the

error. Its value has sense only if the value of `MikMod_errno' is

different from zero. If the value of `MikMod_critical' is zero,

the error wasn't fatal and the library is in a stable state.

However, if it is nonzero, then the library can't be used and has

reseted itself to the uninitialized state. This often means that

the mixing parameters you choose were not supported by the driver,

or that it doesn't has enough voices for your needs if you called

`MikMod_SetNumVoices'.

4.1.2 Sound Settings

--------------------

The following variables control the sound output parameters and their

changes take effect immediately.

`UBYTE md_musicvolume'

Volume of the module. Allowed values range from 0 to 128. The

default value is 128.

`UBYTE md_pansep'

Stereo channels separation. Allowed values range from 0 (no

separation, thus mono sound) to 128 (full channel separation). The

default value is 128.

`UBYTE md_reverb'

Amount of sound reverberation. Allowed values range from 0 (no

reverberation) to 15 (a rough estimate for chaos...). The default

value is 0.

`UBYTE md_sndfxvolume'

Volume of the sound effects. Allowed values range from 0 to 128.

The default value is 128.

`UBYTE md_volume'

Overall sound volume. Allowed values range from 0 to 128. The

default value is 128.

4.1.3 Driver Settings

---------------------

The following variables control more in-depth sound output parameters.

Except for some `md_mode' flags, their changes do not have any effect

until you call `MikMod_Init' or `MikMod_Reset'.

`UWORD md_device'

This variable contains the order, in the list of the registered

drivers, of the sound driver which will be used for sound

playback. This order is one-based; if this variable is set to

zero, the driver is autodetected, which means the list is tested

until a driver is present on the system. The default value is 0,

thus driver is autodetected.

`MDRIVER* md_driver'

This variable points to the driver which is being used for sound

playback, and is undefined when the library is uninitialized

(before `MikMod_Init' and after `MikMod_Exit'). This variable is

for information only, you should never attempt to change its

value. Use `md_driver' and `MikMod_Init' (or `MikMod_Reset')

instead.

`UWORD md_mixfreq'

Sound playback frequency, in hertz. High values yield high sound

quality, but need more computing power than lower values. The

default value is 44100 Hz, which is compact disc quality. Other

common values are 22100 Hz (radio quality), 11025 Hz (phone

quality), and 8000 Hz (mu-law quality).

`UWORD md_mode'

This variable is a combination of several flags, to select which

output mode to select. The following flags have a direct action

to the sound output (i.e. changes take effect immediately):

`DMODE_INTERP'

This flag, if set, enables the interpolated mixers.

Interpolated mixing gives better sound but takes a bit more

time than standard mixing. If the library is built with the

high quality mixer, interpolated mixing is always enabled,

regardless of this flag.

`DMODE_REVERSE'

This flag, if set, exchanges the left and right stereo

channels.

`DMODE_SURROUND'

This flag, if set, enables the surround mixers. Since

surround mixing works only for stereo sound, this flag has no

effect if the sound playback is in mono.

The following flags aren't taken in account until the sound driver

is changed or reset:

`DMODE_16BIT'

This flag, if set, selects 16 bit sound mode. This mode

yields better sound quality, but needs twice more mixing time.

`DMODE_HQMIXER'

This flag, if set, selects the high-quality software mixer.

This mode yields better sound quality, but needs more mixing

time. Of course, this flag has no effect if no

`DMODE_SOFT_xx' flag is set.

`DMODE_SOFT_MUSIC'

This flag, if set, selects software mixing of the module.

`DMODE_SOFT_SNDFX'

This flag, if set, selects software mixing of the sound

effects.

`DMODE_STEREO'

This flag, if set, selects stereo sound.

The default value of this variable is `DMODE_STEREO |

DMODE_SURROUND | DMODE_16BITS | DMODE_SOFT_MUSIC |

DMODE_SOFT_SNDFX'.



File: mikmod.info, Node: Structure Reference, Next: Error Reference, Prev: Variable Reference, Up: Library Reference

4.2 Structure Reference

=======================

Only the useful fields are described here; if a structure field is not

described, you must assume that it's an internal field which must not be

modified.

4.2.1 Drivers

-------------

The `MDRIVER' structure is not meant to be used by anything else than

the core of the library, but its first four fields contain useful

information for your programs:

`CHAR* Name'

Name of the driver, usually never more than 20 characters.

`CHAR* Description'

Description of the driver, usually never more than 50 characters.

`UBYTE HardVoiceLimit'

Maximum number of hardware voices for this driver, 0 if the driver

has no hardware mixing support.

`UBYTE SoftVoiceLimit'

Maximum number of software voices for this driver, 0 if the driver

has no software mixing support.

`CHAR* Alias'

A short name for the driver, without spaces, usually never more

than 10 characters.

4.2.2 Modules