Is the C library used by STM32 MCU based on glibc or musl?

[Shiina]

I want to know what the C library in the GCC toolchain used by STM32 MCUs

[waclawek.jan]

I had to look up what's musl; it appears to be a linux-specific C standard library.

gcc for Cortex-M usually uses newlib-nano.

JW

[Shiina]

ok, thanks

[Pavel A.]

It is newlib, in two variants: "standard" and nano (aka "reduced").