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J. Nick Koston
af1a00ccf9
ESP-IDF SDK components reference fprintf(), printf(), and vprintf() which pull in newlib's _vfprintf_r (~11 KB). This is a separate implementation from _svfprintf_r (used by snprintf/vsnprintf) that handles FILE* stream I/O with buffering and locking. ESPHome replaces the ESP-IDF log handler via esp_log_set_vprintf_(), so the SDK's vprintf() path is dead code at runtime. The fprintf() and printf() calls in SDK components are only in debug/assert paths that are either GC'd or never called. These linker --wrap stubs redirect through vsnprintf() + fwrite(), allowing the linker to dead-code eliminate _vfprintf_r. An escape hatch is provided via enable_full_printf: true in the esp32 advanced config section for external components that need full FILE*-based fprintf.