Arm Mbed OS support forum

Mbed Studio GCC and Intellisense Errors

Although my code builds and runs, when using GCC I am seeing errors in the editor window (red underlines).

  • With ARMC6, there are no red underlines (but I can rarely get debug to work, so I prefer GCC)
  • With GCC 9-2020-q2, the error appears

I should stress the code builds with no warnings or errors.

In the source, the line #include “mbed.h” has a red underline. When I hover, it says:
In included file: 'stdint.h' file not foundclang(pp_file_not_found)

Subsequent lines are also underlined. For example, every printf or uint32_t in the code.

Mbed Studio 1.4.2 - All Tools Updated
Mbed OS 6.15.0
GCC 9-20-q2 as specified in
Host OS: Windows 10
mbed_app.json is shown below:


    "requires": ["bare-metal"],

    "target_overrides": {

        "*": {

            "target.printf_lib": "std",

            "target.c_lib": "std",            

            "platform.stdio-baud-rate": 115200,

            "platform.stdio-buffered-serial": 1




Maybe you need to see this topic. There are problems in a specific version of Mbed Studio.

Thanks - I’ll take a look!