A typedef introduces an alias for an existing C type; it does not create a distinct type. For example, a structure can receive a convenient name before or alongside its declaration: section 6.0 section 6.4
Aliasing a structure tag
typedef struct birdStruct birdStructure; typedef struct birdStruct birdStruct; struct birdStruct { ... }; The identifiers struct birdStruct, birdStruct, and birdStructure can then be used interchangeably for the same structure type. section 6.4
Use typedef according to these rules:
- Alias existing types without treating the aliases as new types. section 6.4
- Forward-declare a structure within a typedef by reusing its tag identifier. section 6.4
- Use implementation-provided names such as size_t for sizes, cardinalities, and ordinal numbers. section 5.2
- Avoid introducing identifiers ending in _t because those names are reserved. section 6.4
typedef double vector[64]; typedef vector vecvec[16]; vecvec A; typedef double matrix[16][64]; matrix B; double C[16][64];
Shows typedef aliases for multidimensional arrays, including equivalent declarations using vector, vecvec, matrix, and a direct array type. section 6.4
