C Numerical & Embedded Engineering Integration (.c, .h)

@modelscript/c (languages/c) provides native WebAssembly GLR parsing, procedural simulation step compilation, automated Modelica external "C" header binding, continuous DAE lowering, and static analysis diagnostics for ANSI C / C99 engineering blocks, Simulink C MEX S-functions, and PSCAD custom C components.

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Supported Extensions & Standards

Extension	Standard / Format	Description
.c	C99 / ANSI C	Control algorithms, filter routines, ODE integration steps, and S-functions
.h	C Headers	Function prototypes, typedefs, and struct layouts for Modelica external bindings

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Key Capabilities

1. WebAssembly GLR C Parser

• Ahead-of-time compiled WebAssembly GLR parser generated by @modelscript/dsl with zero grammar conflicts.
• Parses full C99 translation units, nested functions, struct/union/enum declarations, typedef names, control flow (if, while, for, do-while), pointer/array operators, and bitwise/arithmetic expressions.

2. Automated Modelica External "C" Bridge

• Header Scraper (scrapeCHeader) extracts C prototypes, argument names, causalities, and struct fields from .h files.
• Modelica Binder (bindCHeaderToModelica) auto-generates strongly typed Modelica functions with:

  function motor_torque
    input Real current;
    input MotorParams p;
    output Real y;
    external "C" y = motor_torque(current, p)
      annotation(Include = "#include \"motor.h\"");
  end motor_torque;

3. Zero-Allocation Simulation Step Compiler

• Compiles procedural C control blocks and discrete filters into low-overhead execution closures executing 100,000 steps in < 30ms without heap allocations.
• Direct mapping to pre-allocated typed arrays: statesReal (Float64Array) and statesInt (Int32Array).
• Built-in support for standard <math.h> mathematical functions (sin, cos, tan, asin, acos, atan, atan2, exp, log, log10, sqrt, fabs, pow, fmin, fmax, floor, ceil).

4. Direct DAE Subroutine Lowering

• Translates ODE continuous state derivatives (dx[i] = ... / der_x = ...) directly into continuous states der(s_i) in @modelscript/runtime's IDaeBuilder linear memory arena.
• Enables Simulink continuous S-functions and PSCAD C segments to integrate directly into continuous DAE and hybrid ODE solvers.

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Static Analysis & Safety Linter Rules

The C analyzer surfaces common numeric defects, memory safety concerns, and algorithmic cycles (M8401–M8410):

10 rules3 warning6 error1 info Run with msx lint

Code	Rule	Severity	Message
M8401	uninitialized-variable	warning	Local variable '<varName>' may be read before being initialized.
M8402	constant-division-by-zero	error	Division or modulo by constant zero detected in arithmetic expression.
M8403	array-bounds-overflow	error	Static array subscript '<arrName>[<index>]' exceeds declared dimension bound of <bound>.
M8404	unreachable-code	warning	Unreachable statements detected following unconditional 'return', 'break', or 'goto'.
M8405	assignment-in-conditional	warning	Assignment operator '=' used inside conditional expression; did you mean '=='?
M8406	algebraic-dependency-cycle	error	Procedural algebraic dependency cycle detected without state lag: '<cycle>'.
M8407	null-pointer-dereference	error	Dereference of statically known NULL pointer in expression '<expr>'.
M8408	function-prototype-mismatch	error	Function '<fnName>' signature conflicts with declaration: expected '<expected>', got '<actual>'.
M8409	missing-return-value	error	Non-void function '<fnName>' with return type '<returnType>' reaches end of body without returning a value.
M8410	implicit-lossy-conversion	info	Implicit floating-point to integer conversion from '<fromType>' to '<toType>' may cause lossy truncation.

Generated from languages/c/src/errors.ts. All languages →

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CLI Usage

# Lint C source files or headers
msx lint Controller.c

# Generate Modelica external "C" bindings from header
msx c to-modelica SensorDriver.h -o SensorDriver.mo