Fix MinGW build bug and ACR122U PC/SC reconnect issue on Windows - #765
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doomfrawen wants to merge 1 commit into
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Fix MinGW build bug and ACR122U PC/SC reconnect issue on Windows#765doomfrawen wants to merge 1 commit into
doomfrawen wants to merge 1 commit into
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- contrib/win32/stdlib.c: setenv()/unsetenv() declared 'char *str[32]' (an array of 32 uninitialized pointers) instead of 'char str[32]' (a buffer). Under older GCC this only warned; GCC >= 14 rejects it as an incompatible pointer type, and even when it compiles the original code writes through a garbage pointer. - libnfc/drivers/acr122_pcsc.c: acr122_pcsc_close() disconnected with SCARD_LEAVE_CARD, which on an ACR122U talking through Windows' inbox CCID driver (WUDFUsbccidDriver) leaves the reader's internal session state such that the *next* SCardConnect from any process fails with 'No ACR122 firmware received' until the device is physically replugged. Disconnecting with SCARD_UNPOWER_CARD forces a clean depower/reset of the card interface on close, matching what a physical replug does, and the reader is immediately usable again by the next open.
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Two small, unrelated fixes found while building libnfc for native Windows via MSYS2 MinGW64 with
-DLIBNFC_DRIVER_ACR122_PCSC=ON:1.
contrib/win32/stdlib.c—setenv()/unsetenv()declarechar *str[32](an array of 32 uninitialized pointers) instead ofchar str[32](a buffer), thenstrcpy/strcatinto it. Older GCC only warned about the implicit pointer conversion; GCC 14+ rejects it outright, and even where it does compile this is a write through an uninitialized pointer.2.
libnfc/drivers/acr122_pcsc.c—acr122_pcsc_close()callsSCardDisconnect(..., SCARD_LEAVE_CARD). On an ACR122U behind Windows' inbox CCID driver (WUDFUsbccidDriver), this leaves the reader's internal PC/SC session in a state where the nextSCardConnectfrom any process fails withNo ACR122 firmware received, Error: 00000001until the device is physically unplugged and replugged. This reproduced 100% of the time across many runs (nfc-list, mfoc, mfcuk, mfoc-hardnested) on a genuine ACS ACR122U. Switching toSCARD_UNPOWER_CARDforces a full depower/reset of the card interface on close — electrically similar to a replug — and the reader is immediately reusable by the next process with no manual intervention.Both changes are minimal and platform-scoped (Windows/MinGW only). Happy to adjust style/commit message if you'd like it split into two PRs instead.