A compiler is a program that translates your C++ code to object code, after which it is linked (by the linker) to an executable.

A compiler might emit compile warnings and compile errors.  

How to use Qt Creator to compile C code?

In the project file, add the following lines:

QMAKE_CXX = gcc
QMAKE_CXXFLAGS = -x c

 

How to set the C compiler to the C99 standard in Qt Creator?

In the project file, add the following lines:

QMAKE_C = gcc
QMAKE_CFLAGS = -x c -std=c99

Advice

• Ideally, a program should be statically type safe [5]
• Compile cleanly at high warning levels [1,3]
• Prefer compile errors to runtime errors [2,4]

External links

• Codepad online compiler
• Comeau online compiler
• IDE one online compiler

References

• [1] Herb Sutter, Andrei Alexandrescu. C++ coding standards: 101 rules, guidelines, and best practices. ISBN: 0-32-111358-6. Item 1: 'Compile cleanly at high warning levels'.
• [2] Herb Sutter, Andrei Alexandrescu. C++ coding standards: 101 rules, guidelines, and best practices. ISBN: 0-32-111358-6. Item 14: 'Prefer compile- and link-time errors to run-time errors'.
• [3] Linus Torvalds. Re:[PATCH] Don't compare unsigned variable for <0 in sys_prctl(). 2006-11-28. Retrieved on 2010-09-20. 'Friends don't let friends use [gcc] "-W"'
• [4] C++ Core Guidelines: P.5: Prefer compile-time checking to run-time checking
• [5] C++ Core Guidelines: P.4: Ideally, a program should be statically type safe