Hello, I am trying to develop externals for pure data in c on a system running Fedora. There seems to be little on this topic available online, and what I have found generally glosses over the processing of compiling. I need to be able to write a c text and compile that text into a .pd file. I have a c file that should be well formatted to compile and I found a make statement, yet I still cannot compile. I am not extremely familiar with the processes of compiling like this, but I am attempting to learn.

I have found two articles. The first: http://pdstatic.iem.at/externals-HOWTO/ talks about the idea of developing an external, but glosses over the compiling processes. From this I was able to get a c code that should compile into a pd patch. Now, I need to get this block of c code into a .pd code.

The second article https://mediatech.aalto.fi/~tervos/Tutorial on PD Externals, Tervo and Patynen 2010.pdf provided a make statement that should compile the c code, but its not changing anything with the c file. I still cant open the code with pd. According to the article, I need to change the line that points to my pd executable, which I found in my /bin. I run >make clean; then >make; in the directory containing the make statement, my c text file, and the c object file I complied with gcc. But no pd file is created.

I am at a lost. I need to find a way to use c code to develop .pd patches. I know that it is possible because both these articles give example c code that complies into their patches. Someone please help

You should be getting a .pd_linux file, not a .pd file. I've always used the makefile templatewithout problems.

Hi,

I have downloaded the template, and it looks like it's exactly what I need. So thanks for that!

However, I am having trouble using it still. I followed the makefile instructions, replacing template with the name of my library and adding the name of my hello_world.c file to the sources line. When I enter >make clean; then >make; I get a .pd_linux file and a .o file with the hello_world object like expected. However, after linking the directory to my sources in my pd_extended program, I still cannot make the hello_world object in pd. I get the following error message:

load_object: Symbol "hello_world_setup" not found
hello_world
... couldn't create

which is different than if I had tried to make an object that had no .pd_linux file:

no_pdlinux
... couldn't create

so what does this first line mean? How do I get my .pd_linux into a readable format for pd?

Thanks!

When Pd loads your object, it first looks for a setup function to define things like the object's data space, constructor, methods, arguments, etc. This is a required function. If your object is called [myobject], the function should be called myobject_setup(). So the error message is saying that it tried to load hello_world.pd_linux (in other words, it found it, so that part is right at least), but there is no hello_world_setup() function in the C code.

Take a look again at the helloworld section of the HOWTO you linked for a description of the setup function.

Note that the hello_world_setup() function must also be visible (exported) in the symbol table.