I have a tiny RTOS which does not use glibc and I have written own features (e.g. Tolower) in string.c

When compiling ns am acquiring the error:

common/string.c:11:6: error: conflicting varieties for built-in role ‘tolower’ <-Werror>Is over there a CFLAGS to deal with this?

Update Answer: usage -fno-builtin

tolower is a role from the C library and also its i would is a scheduled identifier for usage as an identifier with exterior linkage, even if you don"t encompass the header whereby it is declared.

You are watching: Conflicting types for built-in function

You might get rid that the warning by using -fno-builtin but the best is merely to chose another name because that tolower.

(C99, 7.1.3p1) "All identifiers with outside linkage in any kind of of the adhering to subclauses (including the future library directions) are constantly reserved for use as identifiers with exterior linkage."


If you"re not utilizing the C typical library for part reason, i won"t tell friend that"s more than likely a bad idea. Also though the builtin role will probably implicitely attach to a libc implementation under details circumstances past your control.

Anyways... One of two people don"t usage -Werror, or append -Wno-error or fix your role to look like the actual thing:

int tolower(int c);


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