How Does `extern 'C'` Solve C and C Linking Compatibility Issues?

Linking C and C : The Necessity of extern "C"{ #include }

In the realm of programming, C and C share a similar syntax, yet their compilation processes diverge significantly. While C compilers anticipate C code when incorporating header files, C headers exhibit a distinct format during compilation. This discrepancy can lead to compatibility issues, rendering the linker unable to connect the two codes.

To address this challenge, we employ the extern "C" directive. This directive essentially informs the C compiler to treat the included C header as C code during compilation. Consequently, the linker can effectively combine C and C codes, preventing potential clashes due to differing application binary interfaces (ABIs).

Specifically, extern "C" serves the following functions:

• When to Use: It should be utilized whenever a C header file is included in a C codebase.
• Compiler/Linker Level: Without extern "C", the C compiler may mangle function names according to its ABI. Meanwhile, the linker encounters difficulties connecting C code to C data.
• Compilation/Linking Effects: Extern "C" ensures compatibility by preventing ABI-related mismatches during compilation and linking. It instructs the C compiler to preserve the original C function names and data structures, allowing for seamless integration with C code.

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