error building implicit function and incompatible integer to pointer conversion

[karasjoh000]

Problem

# CCACHE_DISABLE=true make CMAKE_BUILD_TYPE=Release \
#	CMAKE_INSTALL_PREFIX=$HOME/.neovim.install \
#	CMAKE_EXTRA_FLAGS='-DCMAKE_CXX_COMPILER=/home/jkarasev/intel/oneapi/compiler/2024.0/bin/icpx -DCMAKE_C_COMPILER=/home/jkarasev/intel/oneapi/compiler/2024.0/bin/icx' \
#       DEPS_CMAKE_FLAGS="-DCMAKE_CXX_COMPILER=/home/jkarasev/intel/oneapi/compiler/2024.0/bin/icpx -DCMAKE_C_COMPILER=/home/jkarasev/intel/oneapi/compiler/2024.0/bin/icx"

[ 77%] Building C object src/nvim/CMakeFiles/nvim.dir/os/pty_process_unix.c.o
/home/jkarasev/neovim/src/nvim/os/pty_process_unix.c:232:10: error: call to undeclared function 'ptsname'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
  232 |   return ptsname(ptyproc->tty_fd);
      |          ^
/home/jkarasev/neovim/src/nvim/os/pty_process_unix.c:232:10: note: did you mean 'ttyname'?
/usr/include/unistd.h:799:14: note: 'ttyname' declared here
  799 | extern char *ttyname (int __fd) __THROW;
      |              ^
/home/jkarasev/neovim/src/nvim/os/pty_process_unix.c:232:10: error: incompatible integer to pointer conversion returning 'int' from a function with result type 'const char *' [-Wint-conversion]
  232 |   return ptsname(ptyproc->tty_fd);
      |          ^~~~~~~~~~~~~~~~~~~~~~~~
2 errors generated.
make[3]: *** [src/nvim/CMakeFiles/nvim.dir/build.make:3454: src/nvim/CMakeFiles/nvim.dir/os/pty_process_unix.c.o] Error 1
make[3]: Leaving directory '/home/jkarasev/neovim/build'
make[2]: *** [CMakeFiles/Makefile2:532: src/nvim/CMakeFiles/nvim.dir/all] Error 2
make[2]: Leaving directory '/home/jkarasev/neovim/build'
make[1]: *** [Makefile:156: all] Error 2
make[1]: Leaving directory '/home/jkarasev/neovim/build'
make: *** [Makefile:84: nvim] Error 2

Steps to reproduce

CCACHE_DISABLE=true make CMAKE_BUILD_TYPE=Release \
	CMAKE_INSTALL_PREFIX=$HOME/.neovim.install \
	CMAKE_EXTRA_FLAGS='-DCMAKE_CXX_COMPILER=/home/jkarasev/intel/oneapi/compiler/2024.0/bin/icpx -DCMAKE_C_COMPILER=/home/jkarasev/intel/oneapi/compiler/2024.0/bin/icx' \
	DEPS_CMAKE_FLAGS="-DCMAKE_CXX_COMPILER=/home/jkarasev/intel/oneapi/compiler/2024.0/bin/icpx -DCMAKE_C_COMPILER=/home/jkarasev/intel/oneapi/compiler/2024.0/bin/icx"

Expected behavior

It should compile without error

Neovim version (nvim -v)

fe869a8

Vim (not Nvim) behaves the same?

Did not try this.

Operating system/version

No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 22.04.1 LTS
Release:        22.04
Codename:       jammy

Terminal name/version

ubuntu wsl

$TERM environment variable

tmux-256color

Installation

build from repo

[zeertzjq]

Please provide Ubuntu version. (E.g. from the output of lsb_release -a)

[karasjoh000]

@zeertzjq added ubuntu version.

[karasjoh000]

note a temporary fix seems to be adding this into the CMakeLists.txt:

set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wno-implicit-function-declaration -Wno-int-conversion")
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-implicit-function-declaration -Wno-int-conversion")

but not permanent fix. It can be an Intel compiler issue, because it seems like the implicit function in question did have included header. idk. Maybe some macro logic for headers.

[e-kwsm]

I can reproduce the issue with icx 2023.1.0 on Debian 12.2 (glibc 2.36).

The simplest solution is to add -D_GNU_SOURCE, which satisifies the followings:

• -D_XOPEN_SOURCE=500 for ptsname—500 is the minimum, and -D_GNU_SOURCE sets it to 700
• -D_POSIX_C_SOURCE=200809L for strnlen
• -D_DEFAULT_SOURCE for htobe64

The macros and their required values depend on the glibc version, as specified in the man’s.
See also feature_test_macros(7).

Anyway, I believe this is an icx–glibc problem.

[e-kwsm]

neovim/src/nvim/CMakeLists.txt

Lines 197 to 209 in d667e0e

	if(CMAKE_C_COMPILER_ID STREQUAL "GNU" OR CMAKE_C_COMPILER_ID STREQUAL "Clang")
	if(CMAKE_SYSTEM_NAME STREQUAL "SunOS")
	target_link_libraries(nvim PRIVATE -Wl,--no-undefined -lsocket)
	# workaround for clang-11 on macOS, supported on later versions:
	elseif(NOT APPLE)
	target_link_libraries(nvim PRIVATE -Wl,--no-undefined)
	endif()
	# For O_CLOEXEC, O_DIRECTORY, and O_NOFOLLOW flags on older systems
	# (pre POSIX.1-2008: glibc 2.11 and earlier). #4042
	# For ptsname(). #6743
	target_compile_definitions(main_lib INTERFACE _GNU_SOURCE)
	endif()

#4042, #4094, #6743

[dundargoc]

@e-kwsm @karasjoh000 does #26124 solve this problem?

[e-kwsm]

Yes, it fixes the issue.