CMake generate new temporary directory or temporary filename

tempfile.c

#include <stdio.h>

int main(void){

  char name[L_tmpnam];

  if(tmpnam(name) == NULL){
    printf("Temporary file name: %s\n", name);
    return 0;
  }

  return 1;
}

tempfile.cpp

#include <cstdio>
#include <iostream>

int main(){

  char name[L_tmpnam];

  if(std::tmpnam(name)){
    std::cout << "Temporary file name: " << name << std::endl;
    return 0;
  }

  return 1;
}

tmpdir.cmake

function(get_temp_dir ovar)

find_program(mktemp NAMES mktemp)
if(mktemp)
  execute_process(COMMAND mktemp -d OUTPUT_VARIABLE out OUTPUT_STRIP_TRAILING_WHITESPACE RESULT_VARIABLE ret)
  if(ret EQUAL 0)
    set(${ovar} ${out} PARENT_SCOPE)
    return()
  endif()
endif()


find_program(pwsh NAMES pwsh)
if(pwsh)
  execute_process(COMMAND pwsh -c "[System.IO.Path]::GetTempPath()" OUTPUT_VARIABLE out OUTPUT_STRIP_TRAILING_WHITESPACE RESULT_VARIABLE ret)
  if(ret EQUAL 0)
    string(RANDOM LENGTH 12 _s)
    set(out ${out}${_s})
    file(MAKE_DIRECTORY ${out})
    set(${ovar} ${out} PARENT_SCOPE)
    return()
  endif()
endif()

message(FATAL_ERROR "Could not find mktemp or pwsh to make temporary directory")

endfunction(get_temp_dir)

# demo
get_temp_dir(TEMPDIR)

message(STATUS "temporary directory: ${TEMPDIR}")

tmpfile.cmake

function(get_temp_file ovar)

find_program(mktemp NAMES mktemp)
if(mktemp)
  execute_process(COMMAND mktemp OUTPUT_VARIABLE out OUTPUT_STRIP_TRAILING_WHITESPACE RESULT_VARIABLE ret)
  if(ret EQUAL 0)
    set(${ovar} ${out} PARENT_SCOPE)
    return()
  endif()
endif()

find_program(pwsh NAMES pwsh)
if(pwsh)
  execute_process(COMMAND pwsh -c "New-TemporaryFile | Select -ExpandProperty FullName" OUTPUT_VARIABLE out OUTPUT_STRIP_TRAILING_WHITESPACE RESULT_VARIABLE ret)
  if(ret EQUAL 0)
    set(${ovar} ${out} PARENT_SCOPE)
    return()
  endif()
endif()

message(FATAL_ERROR "Could not find mktemp or pwsh to make temporary file")

endfunction(get_temp_file)

# demo
get_temp_file(TEMPFILE)

message(STATUS "temporary file: ${TEMPFILE}")