sh/exec-slurp via janet_dostring (assuming spork is installed)

main.c

// build:
//
// gcc -O0 -g main.c -I$HOME/.local/include -L$HOME/.local/lib -ljanet

// run:
//
// export LD_LIBRARY_PATH=$HOME/.local/lib
// ./a.out

#include "janet.h"
#include <stdio.h>

int main() {
  JanetTable *env;

  janet_init();

  env = janet_core_env(NULL);
  Janet out;
  int status =
    janet_dostring(env,
                   "(import spork/sh) (sh/exec-slurp `uname`)",
                  "source", &out);

  printf("result: %d\n", status);
  
  printf("is string: %d\n", janet_checktype(out, JANET_STRING));
  printf("is nil: %d\n", janet_checktype(out, JANET_NIL));


  janet_deinit();
}

Try adding janet_loop after the call to janet_dostring. the janet_do* functions do not enter the event loop

EDIT: My mistake, that support is added. however, the result that is returned is not useful.