Difference Between
versus

Inline in C++ vs. Macro in C++: Know the Difference

Shumaila Saeed
By Shumaila Saeed || Published on February 21, 2024
In C++, 'inline' is a keyword that advises the compiler to substitute a function's body at the call site, while a 'macro' is a preprocessor directive that performs textual replacement before compilation.
Inline in C++ vs. Macro in C++

Key Differences

Inline functions in C++ are suggested to the compiler for substitution at the call site, aiming to reduce function call overhead. Macros in C++ are defined using the preprocessor directive #define and are replaced by their values before the compilation process begins.
Shumaila Saeed
Shumaila Saeed
Feb 21, 2024
Inline functions are subject to type checking and follow the C++ type rules, providing safety. Macros are replaced by the preprocessor without any type checking, leading to potential errors if not used carefully.
Shumaila Saeed
Shumaila Saeed
Feb 21, 2024
The compiler may ignore the 'inline' suggestion for various reasons like function complexity. Macros are always expanded by the preprocessor, regardless of complexity, which can lead to code bloat.
Shumaila Saeed
Shumaila Saeed
Feb 21, 2024
Inline functions can use regular C++ syntax and benefit from scope and access specifiers. Macros are simple text replacements and don’t understand C++ scope, leading to possible naming conflicts.
Shumaila Saeed
Shumaila Saeed
Feb 21, 2024
Error reporting in inline functions is more informative, as they are part of the C++ language. Errors in macros can be hard to trace since they are expanded before the actual compilation.
Shumaila Saeed
Shumaila Saeed
Feb 21, 2024
ADVERTISEMENT

Comparison Chart

Compilation Process

Suggested for expansion at compile time.
Textually replaced before compilation.
Shumaila Saeed
Shumaila Saeed
Feb 21, 2024

Type Checking

Subject to C++ type checking.
No type checking, can lead to errors.
Shumaila Saeed
Shumaila Saeed
Feb 21, 2024

Compiler's Role

Compiler may ignore inline suggestion.
Preprocessor always expands macros.
Shumaila Saeed
Shumaila Saeed
Feb 21, 2024

Syntax and Scope

Uses C++ syntax and respects scope.
Simple text replacement, unaware of scope.
Shumaila Saeed
Shumaila Saeed
Feb 21, 2024

Error Reporting

Error reporting is more precise.
Error tracing can be challenging.
Shumaila Saeed
Shumaila Saeed
Feb 21, 2024
ADVERTISEMENT

Inline in C++ and Macro in C++ Definitions

Inline in C++

Inline functions are part of the compiled code, not preprocessor directives.
Inline void greet() { cout << Hello; } is a simple inline function.
Shumaila Saeed
Shumaila Saeed
Jan 24, 2024

Macro in C++

Macros can cause code bloat due to uncontrolled expansion.
#define MAX(a,b) ((a) > (b) ? (a) : (b)) expands every time it's used.
Shumaila Saeed
Shumaila Saeed
Jan 24, 2024

Inline in C++

The compiler may choose not to inline a function, despite the inline keyword.
Inline void largeFunction() { /* complex code */ } might not be inlined.
Shumaila Saeed
Shumaila Saeed
Jan 24, 2024

Macro in C++

Macros do not respect C++ scopes and namespaces.
#define RESET 0 might conflict with other uses of RESET.
Shumaila Saeed
Shumaila Saeed
Jan 24, 2024

Inline in C++

Inline functions can access class members and obey scope rules.
Class Example { inline void display() { cout << data; } };
Shumaila Saeed
Shumaila Saeed
Jan 24, 2024
ADVERTISEMENT

Macro in C++

Macros don't follow C++ type rules and lack type safety.
#define SQUARE(x) x*x can lead to unexpected results due to precedence.
Shumaila Saeed
Shumaila Saeed
Jan 24, 2024

Inline in C++

Inline functions help optimize small, frequently called functions.
Inline double square(double x) { return x * x; } is efficient for small tasks.
Shumaila Saeed
Shumaila Saeed
Jan 24, 2024

Macro in C++

Debugging macros can be challenging due to their textual nature.
#define DEBUG_PRINT(x) cout << x can complicate debugging.
Shumaila Saeed
Shumaila Saeed
Jan 24, 2024

Inline in C++

Inline functions suggest the compiler to replace the function call with its body.
Inline int sum(int a, int b) { return a + b; } reduces function call overhead.
Shumaila Saeed
Shumaila Saeed
Jan 24, 2024

Macro in C++

Macros are preprocessor directives for textual replacement.
#define PI 3.14 replaces PI with 3.14 in the code.
Shumaila Saeed
Shumaila Saeed
Jan 24, 2024

Repeatedly Asked Queries

Do inline functions improve performance?

They can, by eliminating the overhead of function calls for small functions.
Shumaila Saeed
Shumaila Saeed
Feb 21, 2024

Are macros part of the C++ language?

No, they are handled by the preprocessor before compilation.
Shumaila Saeed
Shumaila Saeed
Feb 21, 2024

What is an inline function in C++?

A function suggested to the compiler for substitution at the call site.
Shumaila Saeed
Shumaila Saeed
Feb 21, 2024

Is the 'inline' keyword a strict command to the compiler?

No, it's a suggestion that the compiler can choose to ignore.
Shumaila Saeed
Shumaila Saeed
Feb 21, 2024

Are macros considered good practice in modern C++?

In modern C++, macros are often discouraged in favor of using inline functions, templates, and constants for improved code safety and readability.
Shumaila Saeed
Shumaila Saeed
Feb 21, 2024

What is a macro in C++?

A preprocessor directive that performs textual replacement.
Shumaila Saeed
Shumaila Saeed
Feb 21, 2024

When should I use inline functions?

For small, frequently called functions to reduce call overhead.
Shumaila Saeed
Shumaila Saeed
Feb 21, 2024

How do macros affect compilation time?

They can increase compilation time due to code expansion.
Shumaila Saeed
Shumaila Saeed
Feb 21, 2024

Can inline functions be recursive?

Technically yes, but the compiler typically won't inline recursive calls.
Shumaila Saeed
Shumaila Saeed
Feb 21, 2024

Can macros be used for debugging purposes?

Yes, macros like #ifdef and #ifndef are commonly used for conditional debugging statements in C++.
Shumaila Saeed
Shumaila Saeed
Feb 21, 2024

Are macros language-specific to C++?

No, macros are part of the C and C++ preprocessor and can be used in both languages.
Shumaila Saeed
Shumaila Saeed
Feb 21, 2024

Can macros cause unexpected errors?

Yes, due to lack of type checking and issues with code expansion.
Shumaila Saeed
Shumaila Saeed
Feb 21, 2024

Can macros be redefined or undefined within a program?

Yes, you can redefine or undefine macros within your code using appropriate directives like #undef.
Shumaila Saeed
Shumaila Saeed
Feb 21, 2024

Do macros respect C++ syntax rules?

No, they are simple text replacements and don't understand C++ syntax.
Shumaila Saeed
Shumaila Saeed
Feb 21, 2024

What are the potential drawbacks of using macros?

Macros can be error-prone, as they are simple text replacements and lack type checking. They can also lead to code bloat.
Shumaila Saeed
Shumaila Saeed
Feb 21, 2024

What is conditional compilation with macros?

Conditional compilation allows parts of the code to be included or excluded from compilation based on preprocessor directives, controlled by macros.
Shumaila Saeed
Shumaila Saeed
Feb 21, 2024

Share this page

Link for your blog / website
HTML
Link to share via messenger
About Author
Shumaila Saeed
Written by
Shumaila Saeed
Shumaila Saeed, an expert content creator with 6 years of experience, specializes in distilling complex topics into easily digestible comparisons, shining a light on the nuances that both inform and educate readers with clarity and accuracy.

Popular Comparisons

Trending Comparisons

Smart TV vs. Android TVSmart TV vs. Android TV
Shumaila SaeedShumaila Saeed
December 25, 2023
A Smart TV is an internet-connected television with a variety of apps, while an Android TV is specifically a Smart TV powered by Google's Android TV operating system.
Poem vs. PoetryPoem vs. Poetry
Shumaila SaeedShumaila Saeed
December 25, 2023
A poem is a piece of writing that expresses ideas and emotions with a distinctive style and rhythm; poetry is the art form of writing such pieces.
Seagate Exos x16 vs. Seagate Exos x18Seagate Exos x16 vs. Seagate Exos x18
Shumaila SaeedShumaila Saeed
February 8, 2024
The Seagate Exos X16 offers up to 16TB storage with a focus on high-capacity data centers, while the Exos X18 upgrades to 18TB, enhancing performance and capacity for enterprise demands.
Social Change vs. Cultural ChangeSocial Change vs. Cultural Change
Shumaila SaeedShumaila Saeed
December 25, 2023
Social change refers to shifts in societal structures and institutions, impacting behaviors and relationships among people. Cultural change pertains to alterations in a group's shared beliefs, values, and customs, influencing their way of life.
White Collar Crime vs. Blue Collar CrimeWhite Collar Crime vs. Blue Collar Crime
Shumaila SaeedShumaila Saeed
December 25, 2023
White Collar Crime involves non-violent, financially motivated offenses often committed by professionals, while Blue Collar Crime refers to physical or violent crimes often by manual laborers.
Japanese Eyes vs. Chinese EyesJapanese Eyes vs. Chinese Eyes
Shumaila SaeedShumaila Saeed
December 25, 2023
Japanese Eyes and Chinese Eyes refer to linguistic structures in Japanese and Chinese respectively, each reflecting unique aspects of grammar and syntax.
LTE vs. CDMALTE vs. CDMA
Shumaila SaeedShumaila Saeed
February 4, 2024
LTE (Long Term Evolution) is a 4G wireless communication standard with high-speed data transfer, while CDMA (Code Division Multiple Access) is an older 2G/3G technology for mobile networks.
Plant Cell vs. Animal CellPlant Cell vs. Animal Cell
Shumaila SaeedShumaila Saeed
December 25, 2023
Plant cells have a cell wall and chloroplasts for photosynthesis, while animal cells lack these but have centrioles.
Analog Computer vs. Digital ComputerAnalog Computer vs. Digital Computer
Shumaila SaeedShumaila Saeed
December 25, 2023
An Analog Computer processes continuous data, whereas a Digital Computer processes data in discrete numerical form.
2 Pole Motors vs. 4 Pole Motors2 Pole Motors vs. 4 Pole Motors
Shumaila SaeedShumaila Saeed
December 25, 2023
2 Pole Motors have one pair of magnetic poles and run at higher speeds, while 4 Pole Motors have two pairs of poles and operate at lower speeds, offering higher torque.
NAT vs. PATNAT vs. PAT
Shumaila SaeedShumaila Saeed
March 5, 2024
NAT (Network Address Translation) translates private IP addresses to a public one for internet access. PAT (Port Address Translation) maps multiple private IP addresses to a single public IP using different ports.
Gorilla Glass 3 vs. Gorilla Glass 5Gorilla Glass 3 vs. Gorilla Glass 5
Shumaila SaeedShumaila Saeed
January 1, 2024
Gorilla Glass 3 offers improved scratch resistance and durability compared to its predecessors, while Gorilla Glass 5 focuses on enhanced drop protection and toughness.
Federalists vs. Democratic RepublicansFederalists vs. Democratic Republicans
Shumaila SaeedShumaila Saeed
March 24, 2024
Federalists favored strong central government and commercial economy, while Democratic Republicans advocated states' rights and agrarianism.
Hard Copy vs. Soft CopyHard Copy vs. Soft Copy
Shumaila SaeedShumaila Saeed
December 25, 2023
A Hard Copy is a physical version of a document or file, usually on paper, while a Soft Copy is a digital version of the document, stored electronically.
Inox vs. Stainless SteelInox vs. Stainless Steel
Shumaila SaeedShumaila Saeed
January 10, 2024
Inox is a synonym for stainless steel, used mainly in Europe, while stainless steel is a corrosion-resistant alloy containing chromium.
Gorilla Glass vs. Panda GlassGorilla Glass vs. Panda Glass
Shumaila SaeedShumaila Saeed
January 5, 2024
Gorilla Glass is a highly durable, scratch-resistant glass used in electronic devices, while Panda Glass is a similar protective glass known for its high transparency and toughness.
Consecutive vs. SubsequentConsecutive vs. Subsequent
Shumaila SaeedShumaila Saeed
December 25, 2023
Consecutive refers to events or things following one after another in uninterrupted sequence, whereas subsequent denotes following in time or order, but not necessarily immediately afterward.
Oscar vs. EmmyOscar vs. Emmy
Shumaila SaeedShumaila Saeed
February 20, 2024
The Oscar is an award for cinematic achievements, while the Emmy recognizes excellence in television.
Catapult vs. TrebuchetCatapult vs. Trebuchet
Shumaila SaeedShumaila Saeed
January 4, 2024
A catapult is a ballistic device using tension or torsion to launch projectiles, while a trebuchet is a type of catapult using a counterweight for greater force and distance.
Special Education vs. Inclusive EducationSpecial Education vs. Inclusive Education
Shumaila SaeedShumaila Saeed
February 17, 2024
Special Education is tailored instruction for students with disabilities, while Inclusive Education integrates all students, including those with disabilities, into general education settings.
Batch Fermentation vs. Continuous FermentationBatch Fermentation vs. Continuous Fermentation
Shumaila SaeedShumaila Saeed
February 10, 2024
Batch Fermentation is a finite process where nutrients are added at the start and products are harvested at the end, whereas Continuous Fermentation involves a steady input of nutrients and continuous product harvest.
Term vs. SemesterTerm vs. Semester
Shumaila SaeedShumaila Saeed
December 25, 2023
Term is a general period for any division of the academic year, while Semester specifically refers to half of an academic year.
Compression Wood vs. Tension WoodCompression Wood vs. Tension Wood
Shumaila SaeedShumaila Saeed
December 25, 2023
Compression Wood is a denser, abnormal growth in softwood trees under mechanical stress, whereas Tension Wood is a less dense, fibrous growth in hardwoods under similar stress.
Mother vs. GrandmotherMother vs. Grandmother
Shumaila SaeedShumaila Saeed
February 17, 2024
A mother is a woman who has given birth to or raised a child, while a grandmother is the mother of a person's parent.

Featured Comparisons

New Comparisons