tolower is a macro which converts upper-case characters to lower case, leaving all other characters unchanged. It is only defined when c is an integer in the range EOF to 255.
You can use a compiled subroutine instead of the macro definition by undefining this macro using `#undef tolower'.
_tolower performs the same conversion as tolower, but should only be used when c is known to be an uppercase character (A--Z).### Returns
tolower returns the lower-case equivalent of c when it is a character between A and Z, and c otherwise.
_tolower returns the lower-case equivalent of c when it is a character between A and Z. If c is not one of these characters, the behaviour of _tolower is undefined.
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**Authoritative source**: BUSMASTER DITA help source `tolower.dita`, compiled into `BUSMASTER.CHM` with the application.
