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sx/examples/ffi/1222-ffi-cstring-type.sx
agra 66bdc70bf1 test: group examples into per-category folders
Move examples/*.sx and their expected/ snapshots into per-category
subfolders (examples/<category>/...). Folder = leading filename token,
with ffi-objc/ffi-jni kept whole; filenames are unchanged. The corpus
runner and LSP sweep now discover each category's expected/ dir, while
issues/ stays flat. Example 1058's repo-root-relative companion import
is made file-relative. Path strings embedded in 164 snapshots were
regenerated (path-only changes). Test-layout docs in CLAUDE.md updated.
2026-06-21 14:41:34 +03:00

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// The `cstring` type: ONE pointer to a null-terminated u8 buffer — C's
// `char *`. Crosses extern boundaries verbatim in both directions;
// `?cstring` is the nullable case (null pointer = absent); string
// LITERALS coerce implicitly (terminated constants); arbitrary strings
// materialize via to_cstring; from_cstring is the zero-copy view back.
#import "modules/std.sx";
libc :: #library "c";
strerror_c :: (code: i32) -> cstring extern libc "strerror";
getenv_c :: (name: cstring) -> ?cstring extern libc "getenv";
dlerror_c :: () -> ?cstring extern libc "dlerror";
main :: () -> i32 {
// literal -> cstring param; cstring return -> view
e := strerror_c(2);
v := from_cstring(e);
if v.len < 5 { print("BUG: strerror short\n"); return 1; }
print("strerror ok\n");
// ?cstring: present, absent, and null-returning C call
p := getenv_c("PATH");
if p == null { print("BUG: PATH null\n"); return 2; }
if cstring_len(p!) < 1 { print("BUG: PATH empty\n"); return 3; }
q := getenv_c("NO_SUCH_VAR_ZZZ");
if q != null { print("BUG: missing not null\n"); return 4; }
d := dlerror_c();
if d != null { print("BUG: dlerror non-null\n"); return 5; }
print("?cstring ok\n");
// round trip: built string -> owned cstring -> view -> equality
s := concat("hi-", "there");
c := to_cstring(s);
r := from_cstring(c);
if r != "hi-there" { print("BUG: round trip\n"); return 6; }
if cstring_len(c) != 8 { print("BUG: len\n"); return 7; }
print("round trip ok\n");
return 0;
}