## Example main.c

```C

#include <stdio.h>

#include <stdint.h>

#include "sass/context.h"

union Sass_Value* call_fn_foo(const union Sass_Value* s_args, Sass_Function_Entry cb, struct Sass_Compiler* comp)

{

  // get context/option struct associated with this compiler

  struct Sass_Context* ctx = sass_compiler_get_context(comp);

  struct Sass_Options* opts = sass_compiler_get_options(comp);

  // get information about previous importer entry from the stack

  Sass_Import_Entry import = sass_compiler_get_last_import(comp);

  const char* prev_abs_path = sass_import_get_abs_path(import);

  const char* prev_imp_path = sass_import_get_imp_path(import);

  // get the cookie from function descriptor

  void* cookie = sass_function_get_cookie(cb);

  // we actually abuse the void* to store an "int"

  return sass_make_number((intptr_t)cookie, "px");

}

int main( int argc, const char* argv[] )

{

  // get the input file from first argument or use default

  const char* input = argc > 1 ? argv[1] : "styles.scss";

  // create the file context and get all related structs

  struct Sass_File_Context* file_ctx = sass_make_file_context(input);

  struct Sass_Context* ctx = sass_file_context_get_context(file_ctx);

  struct Sass_Options* ctx_opt = sass_context_get_options(ctx);

  // allocate a custom function caller

  Sass_Function_Entry fn_foo =

    sass_make_function("foo()", call_fn_foo, (void*)42);

  // create list of all custom functions

  Sass_Function_List fn_list = sass_make_function_list(1);

  sass_function_set_list_entry(fn_list, 0, fn_foo);

  sass_option_set_c_functions(ctx_opt, fn_list);

  // context is set up, call the compile step now

  int status = sass_compile_file_context(file_ctx);

  // print the result or the error to the stdout

  if (status == 0) puts(sass_context_get_output_string(ctx));

  else puts(sass_context_get_error_message(ctx));

  // release allocated memory

  sass_delete_file_context(file_ctx);

  // exit status

  return status;

}

```

### Compile main.c

```bash

gcc -c main.c -o main.o

gcc -o sample main.o -lsass

echo "foo { margin: foo(); }" > foo.scss

./sample foo.scss => "foo { margin: 42px }"

```