How Can I Successfully Call C Functions from Within C Code?

Invoking C Functions from Within C Code: A Comprehensive Guide

To integrate a C function into C code, one might consider utilizing the standard idiom "extern "C" void foo()". However, this approach may fail during compilation with g , despite successful compilation with gcc.

To address this issue, adhere to the following steps:

Step 1: Separate Compilation of C and C Code

Compile the C code using:

gcc -c -o somecode.o somecode.c

Compile the C code using:

g++ -c -o othercode.o othercode.cpp

Step 2: Linkage via C Linker

Combine the compiled objects using the C linker:

g++ -o yourprogram somecode.o othercode.o

Step 3: Informing the C Compiler about C Header

Include a declaration for the C function in the C code, preceded by "extern "C" {}:

extern "C" {
#include "somecode.h"
}

Step 4: Declaration in somecode.h

Define the C function in the header file somecode.h:

#ifndef SOMECODE_H_
#define SOMECODE_H_

void foo();

#endif

Note: The commands in this example were for gcc. The fundamental approach remains applicable to any compiler. Compile the code separately for C and C , then link them.

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