Where is the definition of _ccv_identifier_

[wandering007]

There are several occurrences of _ccv_identifier_ in ccv_internal.h:

#define ccv_sign_with_literal(string) \
    char INTERNAL_CATCH_UNIQUE_NAME(_ccv_identifier_)[] = (string); \
    size_t INTERNAL_CATCH_UNIQUE_NAME(_ccv_string_size_) = sizeof(INTERNAL_CATCH_UNIQUE_NAME(_ccv_identifier_));

#define ccv_sign_with_format(size, string, ...) \
    char INTERNAL_CATCH_UNIQUE_NAME(_ccv_identifier_)[(size)]; \
    memset(INTERNAL_CATCH_UNIQUE_NAME(_ccv_identifier_), 0, (size)); \
    snprintf(INTERNAL_CATCH_UNIQUE_NAME(_ccv_identifier_), (size), (string), ##__VA_ARGS__); \
    size_t INTERNAL_CATCH_UNIQUE_NAME(_ccv_string_size_) = (size); 

But I cannot find the definition of it...