GreyCat SDK - C API & Standard Library

Comprehensive reference for GreyCat native development (C API) and the GCL Standard Library.

Contents

1. C API - Native function implementation, tensor operations, object manipulation
2. Standard Library (std) - GCL runtime features, I/O, collections, and utilities

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GreyCat C API

Core Concepts

gc_machine_t - Execution context passed to all native functions. Use to get parameters, set results, report errors, and create objects.

gc_slot_t - Universal value container (union type) holding any GreyCat value: integers, floats, bools, objects, etc.

gc_type_t - Type system enum defining all GreyCat types (null, bool, int, float, str, object, static_field, etc.).

Common Operations

Parameter handling:

gc_slot_t param = gc_machine__get_param(ctx, offset);
gc_type_t type = gc_machine__get_param_type(ctx, offset);

Object field access:

gc_slot_t value = gc_object__get_at(obj, field_offset, &type, ctx);

Tensor operations:

gc_core_tensor_t *tensor = gc_core_tensor__create(ctx);
gc_core_tensor__init_2d(tensor, rows, cols, gc_core_TensorType_f32, ctx);
f32_t val = gc_core_tensor__get_2d_f32(tensor, row, col, ctx);

Memory management:

char *temp = (char *)gc_gnu_malloc(size);      // Per-worker allocator
double *shared = (double *)gc_global_gnu_malloc(size);  // Global allocator

Detailed Reference

File: references/api_reference.md (1,461 lines)

Load when implementing:

• Native C functions with gc_machine_t
• Tensor operations (multi-dimensional arrays)
• Object/field manipulation, type introspection
• Buffer building, string operations
• HTTP client, cryptography, I/O operations

Contains: Complete function signatures, real production examples, and documentation for Machine API, Object API, Tensor API, Array/Table APIs, Buffer/String APIs, Memory Allocation, Program/Type System, HTTP Client, Cryptography, and I/O.

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GreyCat Standard Library (std)

Module Organization

• std::core - Fundamental types (Date, Time, Duration, Tuple, Error, geospatial types, enumerations)
• std::runtime - Scheduler, Task, Job, Logger, User/Security, System, ChildProcess, License, OpenAPI, MCP
• std::io - Text/Binary I/O, CSV, JSON, XML, HTTP client, Email/SMTP, FileWalker
• std::util - Collections (Queue, Stack, SlidingWindow, TimeWindow), Statistics (Gaussian, Histogram), Quantizers, Assert, ProgressTracker, Crypto, Random, Plot

Detailed Reference

File: references/standard_library.md (957 lines)

Load when working with:

• Task scheduling and automation (Scheduler with periodicities)
• File I/O operations (CSV, JSON, XML, binary files)
• HTTP integration and REST APIs
• Statistical analysis and data processing
• Security, authentication, and user management
• System operations and logging

Contains: Complete documentation for all four standard library modules with code examples, usage patterns, and best practices.