Undefined functions do not report errors

[xren5321]

Environment

• OS and Version: win11 Professional Edition 23H2
• VS Code Version: 1.90.2
• C/C++ Extension Version: v1.21.0
• If using SSH remote, specify OS of remote machine: local

Bug Summary and Steps to Reproduce

Bug Summary:

Configuration and Logs

c_cpp_properties.json

{
    "configurations": [
        {
            "name": "STM32F103",
            "includePath": [
                "E:/embedded/vscode/test1/Core/Inc",
                "E:/embedded/vscode/test1/Drivers/CMSIS/Device/ST/STM32F1xx/Include",
                "E:/embedded/vscode/test1/Drivers/CMSIS/Include",
                "E:/embedded/vscode/test1/Drivers/STM32F1xx_HAL_Driver/Inc",
                "E:/embedded/vscode/test1/Drivers/STM32F1xx_HAL_Driver/Inc/Legacy"
            ],
            "browse": {
                "limitSymbolsToIncludedHeaders": false,
                "path": [
                    "E:/embedded/vscode/test1/Drivers/STM32F1xx_HAL_Driver/Src",
                    "E:/embedded/vscode/test1/Drivers/CMSIS/Device/ST/STM32F1xx/Source/Templates"
                ]
            },
            "cStandard": "c17",
            "cppStandard": "gnu++14",
            "defines": [
                "STM32F103xB",
                "USE_HAL_DRIVER",
                ""
            ],
            "compilerPath": "E:/software/VScode/.platformio/packages/toolchain-gccarmnoneeabi/bin/arm-none-eabi-gcc.exe",
            "compilerArgs": [
                "-mthumb",
                "-mcpu=cortex-m3",
                ""
            ],
            "intelliSenseMode": "${default}"
        }
    ],
    "version": 4
}

settings.json 
{
    "files.associations": {
        "main.h": "c",
        "stm32f1xx_hal.h": "c",
        "stm32f1xx_hal_def.h": "c",
        "stddef.h": "c",
        "stm32f1xx.h": "c"
    }
}

Other Extensions

No response

Additional context

This is a cubemx generated makefile format code, I write a random function in the main C/CPP does not give hints

[browntarik]

Could you provide the codebase you are using to reproduce this error?

[browntarik]

After further investigation, it looks like you are facing an existing issue due to by-design behavior from c-compilers. C-compilers process implicit functions as warnings and not errors. Thus, IntelliSense will not squiggle an undefined function with an error squiggle before compilation (see below).

After compilation, you should see a warning flag generated using the -Wimplicit-function-declaration in the c compiler.

More information can be found on another issue addressing this here: https://github.com/microsoft/vscode-cpptools/issues/828

This issue will now be closed as a duplicate. Please let us know if you have further concerns.

[xren5321]

thank you. So is Clang-Tidy supported now？

[sean-mcmanus]

@xren5321 It is, via the Run Code Analysis commands (and C_Cpp.codeAnalysis.* settings).