Warning: conflicting types for built-in function 'puts' Solution

Warning: conflicting types for built-in function 'puts' solution [compiler version] arm-linux-gcc 3.4.1 [Problem description] www.2cto.com when developing the embedded underlying layer, I wrote a puts function, that is, sending a string to the Super Terminal through the serial port. However, the following problems occur during program Compilation: warning: conflicting types for built-in function 'puts' [Problem Analysis] in the C language standard, some common functions are defined as built-in functions (built-in functions), such as printf, puts, strchr, memset, and so on. These functions do not need to contain declarations in header files, you can compile and connect the function. However, if you want to implement it on your own, the conflict prompt shown above will appear. Sometimes you can use the function contained in www.2cto.com without including some header files. It may be that the compiler contains some common simple functions for processing, even if you do not include the header file, the compiler also knows where to find it, but if it is a complex function or a static library you write yourself, you must include it when you want to use it; it's just some simple functions you don't need to include header files. [Solution] 1. Add the-fno-builtin or-fno-builtin-FUNCTION option during compilation, and you can implement these functions without conflict. For example, in the above prompt, you can add-fno-builtin-puts during compilation to compile normally. 2. Change the names of these functions to avoid conflict.