As most embedded programming is currently performed using C, it is likely that developers will need to transition their code and their working practice to C++. This session proposes a strategy that enables the benefits of C++ to be realized quickly and incrementally.

1. Programming Embedded
Systems in C++
A C to C++ Migration Strategy
20 May 2014
Colin Walls, Mentor Graphics
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2. This is what a question slide will
look like.
Please answer in the chat.
Also, questions to me start with ?
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[ # ]

3. Agenda
Monday: C++ for Embedded Programming
Tuesday: C to C++ Migration Strategy
Wednesday: C++ and a Real Time Operating
System
Thursday: Case study #1
Friday: Case Study #2
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4. What language are you
using for embedded
development today?
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5. C to C++ Migration
• Three stage process:
– exploit reusability
• new code in C++
• link with C code
– treat C as C++
• clean up C code to comply with C++
– start using C++ language features
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6. Apply Reusability
• All new code in C++
– link with existing C modules
• Problem with typesafe linkage
– C++ function names and references manged
fun(int) becomes fun_int(int)
– C functions not mangled
fun(int) unchanged
– use extern "C"
extern "C"
{
void funx(int);
int fun(float);
...
}
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7. Clean C
• ANSI C is essentially a subset of C++
• Numerous minor exceptions
• Clean C is true subset
– code written or modified to accommodate exceptions
– still ANSI C
– specific points to address
• Treat Clean C as if it were C++
– acceptable to C++ compiler
– type-safe linkage OK
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8. Clean C
• Function prototypes are mandatory
• Implicit types casts are a problem
– use explicit – like (char)
• Enumerated types are taken “seriously”
• Character arrays must have room for
terminator
char str[3] = "xyz"; is not acceptable
char str[] = "xyz"; is better
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9. Clean C
C:
Nested structures need care
struct out
{
struct in { int i; } m;
int j;
};
struct in inner;
struct out outer;
Clean C:
struct in { int i; };
struct out
{
struct in m;
int j;
};
struct in inner;
struct out outer;
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10. To view the rest of this course,
visit the full recorded version on Design News.
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