1. Demo of -v option to show what compiler does
    gcc -v mswap.c swap.c
2. Demo of missing external function
    gcc  -o mswap mswap.c
3. Full link
    gcc -o mswap mswap.c swap.c
or:
    gcc -c mswap.c swap.c
    gcc -o mswap mswap.o swap.o
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1. strings mswap.o swap.o

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1. gcc mstatic.c static1.c
2. gcc mstatic.c static2.c
3. gcc mstatic.c static3.c

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1. readelf -s swap.o
2. readelf -a swap.o

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1. nm swap.o

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1. g++ -o mangle mangle.C
2. g++ -c mangle.C
3. readelf -s mangle.o

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1. gcc -o mproblem mproblem.c problem.c
2. ./mproblem

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1. size mswap.o
2. size mswap