Faust Build

Faust Build

Compile a Faust DSP source file to C and verify the result is structurally correct. Combines three steps that were performed manually on every DSP change: parameter audit, compilation, and API surface verification. Optionally adds a clang compile step to catch type errors early.

Requirements

• Faust compiler on PATH (or specify binary with --faust). Tested against Faust 2.85.x.
• Known issue: -ftz 2 generates broken C in Faust 2.85.5. This script defaults to -ftz 0 (see --ftz option).
• clang (optional, only needed for --clang step)
• Faust architecture headers (optional, only needed for --clang): the directory containing faust/gui/CInterface.h. Pass via --faust-arch.

Instructions

Arguments are in $ARGUMENTS. Pass them directly to the build script:

bash "$(dirname "$0")/build.sh" $ARGUMENTS

Steps performed

| Step | What it does | |------|--------------| | 0 — Param audit | Scans the .dsp source for hslider/vslider/nentry parameters not followed by si.smoo or si.smooth on the same line. Flags as warnings (heuristic; does not catch multi-line smoothing). | | 1 — Faust compile | Runs faust -lang c -cn -single -ftz -o . Aborts on compiler failure. | | 2 — API surface check | Greps the generated C for all 14 expected public function names (suffix = class name). Checks that FAUSTCLASS macro matches. Optionally verifies getNumInputs and getNumOutputs return values. | | 3 — Clang compile (optional) | Runs clang -std=c11 -O2 -Wall -Wextra -include faust/gui/CInterface.h -Wno-unused-parameter -c . The force-include is required because Faust-generated C references UIGlue, MetaGlue, and Soundfile without including their definitions. |

Options

| Option | Default | Description | |--------|---------|-------------| | --cn NAME | mydsp | Faust class name (-cn flag). All generated function names are suffixed with this. | | -I PATH | — | Include path for Faust library resolution (repeatable). Typically needs dsp/modules and the faustlibraries path. | | --faust BIN | faust | Faust compiler binary path. | | --faust-arch DIR | — | Directory containing faust/gui/CInterface.h. Required for --clang. | | --ftz N | 0 | Faust denormal flushing mode. Use 0 for Faust 2.85.x (the default); -ftz 2 is broken in that version. | | --clang | off | Run clang -c -Wall on the generated C as a final verification step. | | --inputs N | — | Expected getNumInputs return value. Fails if the generated code disagrees. | | --outputs N | — | Expected getNumOutputs return value. Fails if the generated code disagrees. |

Exit codes

• 0 — all checks passed (warnings do not fail the build)
• 1 — Faust compilation failed, or one or more API surface checks failed, or clang failed

Examples

# Minimal: compile and verify API surface
bash build.sh src/dsp/synth.dsp src/generated/synth.c --cn Synth

# With library paths and expected I/O counts
bash build.sh src/dsp/synth.dsp src/generated/synth.c \
  --cn Synth \
  -I dsp/modules \
  -I ~/faust/faustlibraries \
  --inputs 0 --outputs 1

# Full verification including clang
bash build.sh src/dsp/synth.dsp src/generated/synth.c \
  --cn Synth \
  -I dsp/modules \
  -I ~/faust/faustlibraries \
  --faust-arch ~/faust/architecture \
  --clang \
  --inputs 0 --outputs 1

Notes

• -ftz 0 means no Faust-level denormal flushing. Move denormal protection to the driver layer (FTZ/DAZ CPU flags on the audio thread). This is better separation of concerns anyway.
• The param audit checks only within single lines. A parameter smoothed on the next line (e.g. freq = hslider(...)\n : si.smoo) will be flagged as a warning even though it is correctly smoothed. Treat warnings as review prompts, not definitive failures.
• The public API for -cn Synth is: newSynth, deleteSynth, metadataSynth, getSampleRateSynth, getNumInputsSynth, getNumOutputsSynth, classInitSynth, instanceResetUserInterfaceSynth, instanceClearSynth, instanceConstantsSynth, instanceInitSynth, initSynth, buildUserInterfaceSynth, computeSynth. All 14 must be present for a valid build.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: gertsylvest
• Source: gertsylvest/meta-team
• License: MIT

Install and usage instructions live in the source repository linked above.