mulle-objc Value-to-String Conversion Reference

There are many ways to turn a value into a string in this stack. This doc catalogues every one () so you can pick the right tool without guessing.

TLDR — The "I just want sprintf / stringWithFormat:" Cheat Sheet #

These are the six format-string entry points you'll use most often, sorted by memory-management style:

Prefer mulle_buffer_do / mulle_buffer_do_autoreleased_string over mulle_snprintf — they grow as needed, compose naturally, and avoid fixed buffer management bugs.

Reference Table #

Decision Flow #

Pure C, no runtime
├── Need a short-lived temp string?
│   └── mulle_sprintf_do(s, fmt, ...) { use s; }
├── Need a bounded fixed buffer?
│   └── mulle_snprintf(buf, sizeof(buf), fmt, ...)
├── Need a heap-allocated long-lived string?
│   └── mulle_asprintf(&p, fmt, ...)  →  mulle_free(p)
├── Building up incrementally / many appends?
│   └── mulle_buffer_do(buf) { mulle_buffer_sprintf(buf, ...); ... extract_string }
├── Just print to stdout / stderr?
│   └── mulle_printf(fmt, ...)  /  mulle_fprintf(stderr, fmt, ...)
└── Just a float to string?
    └── mulle_dtostr(value, buf)

ObjC runtime available
├── Want autoreleased C string (no manual free)?
│   ├── MulleObjC_asprintf(fmt, ...)
│   └── mulle_buffer_do_autoreleased_string(buf, NULL, s) { build; }
├── Want autoreleased C string for a value type?
│   └── CGRectUTF8String(rect), etc.
├── Need an NSString (for containers, etc.)?
│   └── [NSString stringWithFormat:...]
└── Implementing -UTF8String?
    └── mulle_buffer_do_autoreleased_string(buf, NULL, s) { format; }  return s;

Memory-Management Rules of Thumb #

When Each Layer Is Available #