Does CMake always generate configurations for all

I have specific configuration for debug and release options (diferent for MSVC and for GCC). Say we generate default project via cmake ... Does CMake always generate configurations for all possible project configurations (Debug and Release) or one always gets only one set of comfiguration options?

As @cplusplusrat has commented, this depends on the generator/build environment:

For multi-configuration environments like MSVC or XCode, yes.
For single-configuration environments like GCC, no.

And the default for single-configuration environments is neither Debug nor Release (see here or here).

So I have always defined one CMAKE_BUILD_TYPE for single-configuration environments as a default. You could also do this e.g. in build scripts calling CMake:

mingw_build.cmd

@ECHO off
SETLOCAL ENABLEDELAYEDEXPANSION
:: usage:
::          mingw_build.cmd <target> <config>
::                  <target> - target to be built (default: all)
::                  <config> - configuration to be used for build (default: Debug)

if NOT "%1" == "" (set CMAKE_TARGET=%1) else (set CMAKE_TARGET=all)
if NOT "%2" == "" (set CMAKE_BUILD_TYPE=%2) else (set CMAKE_BUILD_TYPE=Debug)
SET CMAKE_BINARY_DIR=%CMAKE_BUILD_TYPE%

IF NOT EXIST "%CMAKE_BINARY_DIR%\Makefile" (
    cmake -H"." -B"%CMAKE_BINARY_DIR%" -DCMAKE_BUILD_TYPE=%CMAKE_BUILD_TYPE% -G"MinGW Makefiles"
)
cmake --build %CMAKE_BINARY_DIR% --target %CMAKE_TARGET%

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vs_x64_build.cmd

@ECHO off
SETLOCAL ENABLEDELAYEDEXPANSION
:: usage:
::          vs_x64_build.cmd <target> <config>
::                  <target> - target to be built (default: ALL_BUILD)
::                  <config> - configuration to be used for build (default: Debug)

if NOT "%1" == "" (SET CMAKE_TARGET=%1) else (SET CMAKE_TARGET=ALL_BUILD)
if NOT "%2" == "" (set CMAKE_BUILD_TYPE=%2) else (set CMAKE_BUILD_TYPE=Debug)
SET CMAKE_BINARY_DIR=x64

IF NOT EXIST "%CMAKE_BINARY_DIR%\*.sln" (
    cmake -H"." -B"%CMAKE_BINARY_DIR%" -G"Visual Studio 14 2015 Win64"
)
cmake --build "%CMAKE_BINARY_DIR%" --target "%CMAKE_TARGET%" --config "%CMAKE_BUILD_TYPE%"

ENDLOCAL