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MPLAB® XC16 C Compiler User Guide
Notice to Development Tools Customers
1 Preface
1.1 GNU Free Documentation License Notice
1.2 Conventions Used in This Guide
1.3 Recommended Reading
2 Compiler Overview
2.1 Device Description
2.2 Compiler Description and Documentation
3 Compiler and Other Development Tools
4 Common C Interface
4.1 Background – The Desire for Portable Code
4.2 Using the CCI
4.3 ANSI Standard Refinement
4.4 ANSI Standard Extensions
4.5 Compiler Features
5 How To's
5.1 Installing and Activating the Compiler
5.2 Invoking the Compiler
5.3 Writing Source Code
5.4 Getting My Application to Do What I Want
5.5 Understanding the Compilation Process
5.6 Fixing Code That Does Not Work
6 XC16 Toolchain and MPLAB X IDE
6.1 MPLAB X IDE and Tools Installation
6.2 MPLAB X IDE Setup
6.3 MPLAB X IDE Projects
6.4 Operation Summary
6.5 References
6.6 Project Setup
6.7 Project Example
7 Compiler Command-Line Driver
7.1 Invoking the Compiler
7.2 The Compilation Sequence
7.3 Runtime Files
7.4 Compiler Output
7.5 Compiler Messages
7.6 Driver Option Descriptions
7.7 MPLAB X IDE Toolchain Equivalents
8 Device-Related Features
8.1 Device Support
8.2 Device Header Files
8.3 Stack
8.4 Configuration Bit Access
8.5 Using SFRs
8.6 Bit-Reversed and Modulo Addressing
8.7 Using EDS
8.8 Stack Usage Guidance
9 Differences Between MPLAB XC16 and ANSI C
9.1 Divergence from the ANSI C Standard
9.2 Extensions to the ANSI C Standard
9.3 Implementation-Defined Behavior
10 Supported Data Types and Variables
10.1 Identifiers
10.2 Integer Data Types
10.3 Floating-Point Data Types
10.4 Fixed-Point Data Types
10.5 Structures and Unions
10.6 Pointer Types
10.7 Literal Constant Types and Formats
10.8 Standard Type Qualifiers
10.9 Compiler-Specific Type Qualifiers
10.10 Variable Attributes
11 Fixed-Point Arithmetic Support
11.1 Enabling Fixed-Point Arithmetic Support
11.2 Data Types
11.3 Rounding
11.4 Division By Zero
11.5 External Definitions
11.6 Mixing C and Assembly Language Code
12 Memory Allocation and Access
12.1 Address Spaces
12.2 Variables In Data Space Memory
12.3 Variables in Program Space
12.4 Parallel Master Port Access
12.5 External Memory Access
12.6 Extended Data Space Access
12.7 Dataflash Memory Access
12.8 Dual Partition Memory Access
12.9 Packing Data Stored in Flash
12.10 Allocation of Variables to Registers
12.11 Variables in EEPROM Data Space (Device Dependent)
12.12 Dynamic Memory Allocation
12.13 Co-Resident Applications
12.14 Memory Models
13 Operators and Statements
13.1 Built-In Functions
13.2 Integral Promotion
14 Register Usage
14.1 Register Variables
14.2 Changing Register Contents
15 Functions
15.1 Writing Functions
15.2 Function Size Limits
15.3 Allocation of Function Code
15.4 Changing the Default Function Allocation
15.5 Inline Functions
15.6 Memory Models
15.7 Function Call Conventions
16 Interrupts
16.1 Interrupt Operation
16.2 Writing an Interrupt Service Routine
16.3 Specifying the Interrupt Vector
16.4 Interrupt Service Routine Context Saving
16.5 Nesting Interrupts
16.6 Enabling/Disabling Interrupts
16.7 ISR Considerations
17 Main, Runtime Startup and Reset
17.1 The main Function
17.2 Runtime Startup and Initialization
18 Mixing C and Assembly Code
18.1 Mixing Assembly Language and C Variables and Functions
18.2 Using Inline Assembly Language
18.3 Predefined Assembly Macros
19 Library Routines
20 Optimizations
20.1 Optimization Feature Summary
20.2 How to Enable Optimization
20.3 Using Optimizations
21 Preprocessing
21.1 C Language Comments
21.2 Preprocessing Directives
21.3 Predefined Macro Names
22 Linking Programs
22.1 Default Memory Spaces
22.2 Replacing Library Symbols
22.3 Linker-Defined Symbols
22.4 Default Linker Script
23 Implementation-Defined Behavior
23.1 Translation
23.2 Environment
23.3 Identifiers
23.4 Characters
23.5 Integers
23.6 Floating Point
23.7 Arrays and Pointers
23.8 Registers
23.9 Structures, Unions, Enumerations and Bit-Fields
23.10 Qualifiers
23.11 Declarators
23.12 Statements
23.13 Preprocessing Directives
23.14 Library Functions
23.15 Signals
23.16 Streams and Files
23.17 tmpfile
23.18 errno
23.19 Memory
23.20 abort
23.21 exit
23.22 getenv
23.23 system
23.24 strerror
24 Embedded Compiler Compatibility Mode
24.1 Compiling in Compatibility Mode
24.2 Syntax Compatibility
24.3 Data Type
24.4 Operator
24.5 Extended Keywords
24.6 Intrinsic Functions
24.7 Pragmas
25 Diagnostics
25.1 Errors
25.2 Warnings
26 GNU Free Documentation License
27 Deprecated Features
27.1 Predefined Constants
27.2 Variables in Specified Registers
27.3 Changing Non-Auto Variable Allocation
27.4 Configuration Settings Using Macros
28 Built-in Functions
28.1 Built-In Functions vs. Inline Assembly
28.2 Built-In Function Descriptions
29 Document Revision History
29.1 Revision M (January 2022)
29.2 Revision L (February 2021)
29.3 Revision K (June 2020)
29.4 Revision J (December 2019)
29.5 Revision H (November 2018)
29.6 Revision G (February 2018)
29.7 Revision F (July 2016)
29.8 Revision E (December 2014)
29.9 Revision D (August 2014)
29.10 Revision C (September 2013)
29.11 Revision B (July 2012)
29.12 Revision A (April 2012)
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