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libterm API Reference

libterm is a small z88dk static library (libterm.lib) available on Spectranext SDK. It redirects standard output from C programs to a dedicated I/O port that Spectranext decodes; the firmware captures that and forwards it over USB CDC when a host is connected (see Logging and terminal stdout).

Paging and Non-Paging versions not required

Unlike other libraries, libterm does not require separation as implementation does not depend on paging. Even when unpaged, libterm can produces output by means of a port output.

I/O port​

Characters are sent with:

OUT (C), A    with BC = $043B

Spectranext treats writes whose bus address satisfies (address & $043B) == $043B as terminal stdout bytes. Using BC = $043B in Z80 OUT (c), a matches that decode.

Provided symbols​

The library includes assembly objects such as:

  • spectranext_fputc_cons / _spectranext_fputc_cons — console character output used by the z88dk console/fputc path for the Spectrum target.

Exact object files are listed in spectranet-firmware/z88dk/libterm/libterm.lst at build time.

Linkage (z88dk / CMake)​

Link libterm together with libspectranet (and your usual Spectranext SDK flags). You must also link either the minimal C runtime libndos or the SPDOS filesystem library libspdos:

ScenarioTypical libraries
No VFS/filesystem in C, only printf / stdoutlibndos, libterm, libspectranet
Using open / read / write via SPDOSlibspdos (instead of libndos), libterm, libspectranet

Classic z88dk stdio expects a writebyte implementation for file-descriptor stdout. That comes from libndos or libspdos. If you link libterm without either, you will get an undefined symbol: writebyte link error.

Either libndos or libspdos must be linked whenever you use libterm.

You must also pass -pragma-redirect:fputc_cons=spectranext_fputc_cons to the linker (see your SDK / example CMake project).

CMake example (Spectranext SDK)​

target_link_options(myprogram PUBLIC
    -pragma-redirect:fputc_cons=spectranext_fputc_cons
)
target_link_libraries(myprogram PUBLIC
    -lndos
    -llibterm
    -llibspectranet.lib
)

With SPDOS instead of ndos (same fputc_cons redirect):

target_link_options(myprogram PUBLIC
    -pragma-redirect:fputc_cons=spectranext_fputc_cons
)
target_link_libraries(myprogram PUBLIC
    -llibspdos.lib
    -llibterm.lib
    -llibspectranet.lib
)

Keep libterm after the runtime library you choose so that the intended stdout/console behaviour is resolved consistently (follow your SDK’s usual link order if documented).

Building and installing​

libterm is part of Spectranext SDK.

See also​