Example of realpath function in C

Question

I\'m looking for an example of how to use the realpath function in a C program. I can\'t seem to find one on the web or in any of my C programming books.

Answer 1

One-line build command line

Minimalist but it does the job!

Build

gcc -o realpath -x c - <<< $'#include\n#include\nint main(int c,char**v){puts(realpath(v[1],0));}'

Test

$> ./realpath  ~/../../../usr/./bin/./awk
/bin/gawk 

$> readlink -f ~/../../../usr/./bin/./awk
/bin/gawk

Requirements

• gcc for compilation and link
• bash for <<< and $' ... \n ... '

Crash

My minimalist one-line command line builds an executable realpath that produces a Segmentation fault when the path does not exist. Instead of writing if/else blocs to handle that issue within my answer, I have added below some links to let you have a look on the Busybox implementation of realpath and readlink.

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Busybox implementation

For a more complete source code, have a look on this simple implementation.

Official Git repository

• coreutils/realpath.c
• coreutils/readlink.c
• libbb/xreadlink.c

GitHub mirror repository

• coreutils/realpath.c
• coreutils/readlink.c
• libbb/xreadlink.c