5 calls to drupal_mkdir()

drupal_install_mkdir in drupal/includes/install.inc
Creates a directory with the specified permissions.
FileTestCase::createDirectory in drupal/modules/simpletest/tests/file.test
Create a directory and assert it exists.
file_prepare_directory in drupal/includes/file.inc
Checks that the directory exists and is writable.
RetrieveFileTestCase::testFileRetrieving in drupal/modules/system/system.test
Invokes system_retrieve_file() in several scenarios.
system_check_directory in drupal/modules/system/system.module
Checks the existence of the directory specified in $form_element.